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Sen C, Logashree V, Makde RD, Ghosh B. Amino acid propensities for secondary structures and its variation across protein structures using exhaustive PDB data. Comput Biol Chem 2024; 110:108083. [PMID: 38691894 DOI: 10.1016/j.compbiolchem.2024.108083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 03/26/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024]
Abstract
Amino acid propensities for protein secondary structures are vital for protein structure prediction, understanding folding, and design, and have been studied using various theoretical and experimental methods. Traditional assessments of average propensities using statistical methods have been done on relatively smaller dataset for only a few secondary structures. They also involve averaging out the environmental factors and lack insights into consistency of preferences across diverse protein structures. While a few studies have explored variations in propensities across protein structural classes and folds, exploration of such variations across protein structures remains to be carried out. In this work, we have revised the average propensities for all six different secondary structures, namely α-helix, β-strand, 310-helix, π-helix, turn and coil, analyzing the most exhaustive dataset available till date using two robust secondary structure assignment algorithms, DSSP and STRIDE. The propensities evaluated here can serve as a standard reference. Moreover, we present here, for the first time, the propensities within individual protein structures and investigated how the preferences of residues and more interestingly, of their groups formed based on their structural features, vary across different unique structures. We devised a novel approach- the minimal set analysis, based on the propensity distribution of residues, which along with the group propensities led us to the conclusion that a residue's preference for a specific secondary structure is primarily dictated by its side chain's structural features. The findings in this study provide a more insightful picture of residues propensities and can be useful in protein folding and design studies.
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Affiliation(s)
- Chandra Sen
- Beamline Development & Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - V Logashree
- Department of Electrical Engineering, Indian Institute of Technology, Indore 453552, India
| | - Ravindra D Makde
- Beamline Development & Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Biplab Ghosh
- Beamline Development & Application Section, Bhabha Atomic Research Centre, Mumbai 400085, India; Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India.
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2
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Pandey AK, Ganguly HK, Sinha SK, Daniels KE, Yap GPA, Patel S, Zondlo NJ. An Inherent Difference between Serine and Threonine Phosphorylation: Phosphothreonine Strongly Prefers a Highly Ordered, Compact, Cyclic Conformation. ACS Chem Biol 2023; 18:1938-1958. [PMID: 37595155 DOI: 10.1021/acschembio.3c00068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/20/2023]
Abstract
Phosphorylation and dephosphorylation of proteins by kinases and phosphatases are central to cellular responses and function. The structural effects of serine and threonine phosphorylation were examined in peptides and in proteins, by circular dichroism, NMR spectroscopy, bioinformatics analysis of the PDB, small-molecule X-ray crystallography, and computational investigations. Phosphorylation of both serine and threonine residues induces substantial conformational restriction in their physiologically more important dianionic forms. Threonine exhibits a particularly strong disorder-to-order transition upon phosphorylation, with dianionic phosphothreonine preferentially adopting a cyclic conformation with restricted ϕ (ϕ ∼ -60°) stabilized by three noncovalent interactions: a strong intraresidue phosphate-amide hydrogen bond, an n → π* interaction between consecutive carbonyls, and an n → σ* interaction between the phosphate Oγ lone pair and the antibonding orbital of C-Hβ that restricts the χ2 side-chain conformation. Proline is unique among the canonical amino acids for its covalent cyclization on the backbone. Phosphothreonine can mimic proline's backbone cyclization via noncovalent interactions. The preferred torsions of dianionic phosphothreonine are ϕ,ψ = polyproline II helix > α-helix (ϕ ∼ -60°); χ1 = g-; χ2 ∼ +115° (eclipsed C-H/O-P bonds). This structural signature is observed in diverse proteins, including in the activation loops of protein kinases and in protein-protein interactions. In total, these results suggest a structural basis for the differential use and evolution of threonine versus serine phosphorylation sites in proteins, with serine phosphorylation typically inducing smaller, rheostat-like changes, versus threonine phosphorylation promoting larger, step function-like switches, in proteins.
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Affiliation(s)
- Anil K Pandey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Himal K Ganguly
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sudipta Kumar Sinha
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
- Department of Chemistry, Indian Institute of Technology Ropar, Nangal Road, Rupnagar 140001, India
| | - Kelly E Daniels
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Sandeep Patel
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Neal J Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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3
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Torrez RM, Nagaraja S, Menon A, Chang L, Ohi MD, Garner AL. Comparative Biochemical Studies of Disease-Associated Human Dicer Mutations on Processing of a Pre-microRNA and snoRNA. Biochemistry 2023. [PMID: 37130292 DOI: 10.1021/acs.biochem.2c00687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Dicer is an RNase III enzyme that is responsible for the maturation of small RNAs such as microRNAs. As Dicer's cleavage products play key roles in promoting cellular homeostasis through the fine-tuning of gene expression, dysregulation of Dicer activity can lead to several human diseases, including cancers. Mutations in Dicer have been found to induce tumorigenesis and lead to the development of a rare pleiotropic tumor predisposition syndrome found in children and young adults called DICER1 syndrome. These patients harbor germline and somatic mutations in Dicer that lead to defective microRNA processing and activity. While most mutations occur within Dicer's catalytic RNase III domains, alterations within the Platform-PAZ (Piwi-Argonaute-Zwille) domain also cause loss of microRNA production. Using a combination of in vitro biochemical and cellular studies, we characterized the effect of disease-relevant Platform-PAZ-associated mutations on the processing of a well-studied oncogenic microRNA, pre-microRNA-21. We then compared these results to those of a representative from another Dicer substrate class, the small nucleolar RNA, snord37. From this analysis, we provide evidence that mutations within the Platform-PAZ domain result in differential impacts on RNA binding and processing, adding new insights into the complexities of Dicer processing of small RNA substrates.
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Affiliation(s)
- Rachel M Torrez
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Shruti Nagaraja
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
| | - Arya Menon
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
| | - Louise Chang
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
| | - Melanie D Ohi
- Life Sciences Institute, University of Michigan, 210 Washtenaw Avenue, Ann Arbor, Michigan 48109, United States
- Department of Cell and Developmental Biology, University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
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4
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Khare E, Grewal DS, Buehler MJ. Bond clusters control rupture force limit in shear loaded histidine-Ni 2+ metal-coordinated proteins. NANOSCALE 2023; 15:8578-8588. [PMID: 37092811 DOI: 10.1039/d3nr01287e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Dynamic noncovalent interactions are pivotal to the structure and function of biological proteins and have been used in bioinspired materials for similar roles. Metal-coordination bonds, in particular, are especially tunable and enable control over static and dynamic properties when incorporated into synthetic materials. Despite growing efforts to engineer metal-coordination bonds to produce strong, tough, and self-healing materials, the systematic characterization of the exact contribution of these bonds towards mechanical strength and the effect of geometric arrangements is missing, limiting the full design potential of these bonds. In this work, we engineer the cooperative rupture of metal-coordination bonds to increase the rupture strength of metal-coordinated peptide dimers. Utilizing all-atom steered molecular dynamics simulations on idealized bidentate histidine-Ni2+ coordinated peptides, we show that histidine-Ni2+ bonds can rupture cooperatively in groups of two to three bonds. We find that there is a strength limit, where adding additional coordination bonds does not contribute to the additional increase in the protein rupture strength, likely due to the highly heterogeneous rupture behavior exhibited by the coordination bonds. Further, we show that this coordination bond limit is also found natural metal-coordinated biological proteins. Using these insights, we quantitatively suggest how other proteins can be rationally designed with dynamic noncovalent interactions to exhibit cooperative bond breaking behavior. Altogether, this work provides a quantitative analysis of the cooperativity and intrinsic strength limit for metal-coordination bonds with the aim of advancing clear guiding molecular principles for the mechanical design of metal-coordinated materials.
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Affiliation(s)
- Eesha Khare
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Laboratory for Atomistic and Molecular Mechanics, Massachusetts Institute of Technology, 33 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Darshdeep S Grewal
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
- Laboratory for Atomistic and Molecular Mechanics, Massachusetts Institute of Technology, 33 Massachusetts Avenue, Cambridge, MA 02139, USA.
| | - Markus J Buehler
- Laboratory for Atomistic and Molecular Mechanics, Massachusetts Institute of Technology, 33 Massachusetts Avenue, Cambridge, MA 02139, USA.
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5
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Zahn T, Zhu Z, Ritoff N, Krapf J, Junker A, Altmann T, Schmutzer T, Tüting C, Kastritis PL, Babben S, Quint M, Pillen K, Maurer A. Novel exotic alleles of EARLY FLOWERING 3 determine plant development in barley. JOURNAL OF EXPERIMENTAL BOTANY 2023:erad127. [PMID: 37010230 DOI: 10.1093/jxb/erad127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 06/19/2023]
Abstract
EARLY FLOWERING 3 (ELF3) is an important regulator of various physiological and developmental processes and hence may serve to improve plant adaptation which will be substantial for future plant breeding. To expand the limited knowledge on barley ELF3 in determining agronomic traits, we conducted field studies with heterogeneous inbred families (HIFs) derived from selected lines of the wild barley nested association mapping population HEB-25. During two growing seasons, phenotypes of nearly isogenic HIF sister lines, segregating for exotic and cultivated alleles at the ELF3 locus, were compared for ten developmental and yield-related traits. We determine novel exotic ELF3 alleles and show that HIF lines, carrying the exotic ELF3 allele, accelerated plant development compared to the cultivated ELF3 allele, depending on the genetic background. Remarkably, the most extreme effects on phenology could be attributed to one exotic ELF3 allele differing from the cultivated Barke ELF3 allele in only one SNP. This SNP causes an amino acid substitution (W669G), which predictively has an impact on the protein structure of ELF3, thereby possibly affecting phase separation behaviour and nano-compartment formation of ELF3 and, potentially, also affecting its local cellular interactions causing significant trait differences between HIF sister lines.
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Affiliation(s)
- Tanja Zahn
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
| | - Zihao Zhu
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 5, 06120, Halle (Saale), Germany
| | - Niklas Ritoff
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
| | - Jonathan Krapf
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
| | - Astrid Junker
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Stadt Seeland, Germany
| | - Thomas Altmann
- Department of Molecular Genetics, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Stadt Seeland, Germany
| | - Thomas Schmutzer
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
| | - Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle (Saale), Germany
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle (Saale), Germany
- Biozentrum, Martin Luther University Halle-Wittenberg, Weinbergweg 22, 06120, Halle (Saale), Germany
| | - Steve Babben
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 5, 06120, Halle (Saale), Germany
| | - Marcel Quint
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 5, 06120, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv), Halle-Jena-Leipzig, Germany
| | - Klaus Pillen
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
| | - Andreas Maurer
- Institute of Agricultural and Nutritional Sciences, Chair of Plant Breeding, Martin Luther University Halle-Wittenberg, Betty-Heimann-Str. 3, 06120, Halle (Saale), Germany
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6
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Daniecki NJ, Bhatt MR, Yap GPA, Zondlo NJ. Proline C-H Bonds as Loci for Proline Assembly via C-H/O Interactions. Chembiochem 2022; 23:e202200409. [PMID: 36129371 DOI: 10.1002/cbic.202200409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/20/2022] [Indexed: 01/25/2023]
Abstract
Proline residues within proteins lack a traditional hydrogen bond donor. However, the hydrogens of the proline ring are all sterically accessible, with polarized C-H bonds at Hα and Hδ that exhibit greater partial positive character and can be utilized as alternative sites for molecular recognition. C-H/O interactions, between proline C-H bonds and oxygen lone pairs, have been previously identified as modes of recognition within protein structures and for higher-order assembly of protein structures. In order to better understand intermolecular recognition of proline residues, a series of proline derivatives was synthesized, including 4R-hydroxyproline nitrobenzoate methyl ester, acylated on the proline nitrogen with bromoacetyl and glycolyl groups, and Boc-4S-(4-iodophenyl)hydroxyproline methyl amide. All three derivatives exhibited multiple close intermolecular C-H/O interactions in the crystallographic state, with H⋅⋅⋅O distances as close as 2.3 Å. These observed distances are well below the 2.72 Å sum of the van der Waals radii of H and O, and suggest that these interactions are particularly favorable. In order to generalize these results, we further analyzed the role of C-H/O interactions in all previously crystallized derivatives of these amino acids, and found that all 26 structures exhibited close intermolecular C-H/O interactions. Finally, we analyzed all proline residues in the Cambridge Structural Database of small-molecule crystal structures. We found that the majority of these structures exhibited intermolecular C-H/O interactions at proline C-H bonds, suggesting that C-H/O interactions are an inherent and important mode for recognition of and higher-order assembly at proline residues. Due to steric accessibility and multiple polarized C-H bonds, proline residues are uniquely positioned as sites for binding and recognition via C-H/O interactions.
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Affiliation(s)
- Noah J Daniecki
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Megh R Bhatt
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Glenn P A Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
| | - Neal J Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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7
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Valanciute A, Nygaard L, Zschach H, Maglegaard Jepsen M, Lindorff-Larsen K, Stein A. Accurate protein stability predictions from homology models. Comput Struct Biotechnol J 2022; 21:66-73. [PMID: 36514339 PMCID: PMC9729920 DOI: 10.1016/j.csbj.2022.11.048] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
Calculating changes in protein stability (ΔΔG) has been shown to be central for predicting the consequences of single amino acid substitutions in protein engineering as well as interpretation of genomic variants for disease risk. Structure-based calculations are considered most accurate, however the tools used to calculate ΔΔGs have been developed on experimentally resolved structures. Extending those calculations to homology models based on related proteins would greatly extend their applicability as large parts of e.g. the human proteome are not structurally resolved. In this study we aim to investigate the accuracy of ΔΔG values predicted on homology models compared to crystal structures. Specifically, we identified four proteins with a large number of experimentally tested ΔΔGs and templates for homology modeling across a broad range of sequence identities, and selected three methods for ΔΔG calculations to test. We find that ΔΔG-values predicted from homology models compare equally well to experimental ΔΔGs as those predicted on experimentally established crystal structures, as long as the sequence identity of the model template to the target protein is at least 40%. In particular, the Rosetta cartesian_ddg protocol is robust against the small perturbations in the structure which homology modeling introduces. In an independent assessment, we observe a similar trend when using ΔΔGs to categorize variants as low or wild-type-like abundance. Overall, our results show that stability calculations performed on homology models can substitute for those on crystal structures with acceptable accuracy as long as the model is built on a template with sequence identity of at least 40% to the target protein.
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Affiliation(s)
- Audrone Valanciute
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Lasse Nygaard
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Henrike Zschach
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Michael Maglegaard Jepsen
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark,Corresponding authors.
| | - Amelie Stein
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen, Denmark,Corresponding authors.
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8
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Local Backbone Geometry Plays a Critical Role in Determining Conformational Preferences of Amino Acid Residues in Proteins. Biomolecules 2022; 12:biom12091184. [PMID: 36139023 PMCID: PMC9496368 DOI: 10.3390/biom12091184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022] Open
Abstract
The definition of the structural basis of the conformational preferences of the genetically encoded amino acid residues is an important yet unresolved issue of structural biology. In order to gain insights into this intricate topic, we here determined and compared the amino acid propensity scales for different (φ, ψ) regions of the Ramachandran plot and for different secondary structure elements. These propensities were calculated using the Chou–Fasman approach on a database of non-redundant protein chains retrieved from the Protein Data Bank. Similarities between propensity scales were evaluated by linear regression analyses. One of the most striking and unexpected findings is that distant regions of the Ramachandran plot may exhibit significantly similar propensity scales. On the other hand, contiguous regions of the Ramachandran plot may present anticorrelated propensities. In order to provide an interpretative background to these results, we evaluated the role that the local variability of protein backbone geometry plays in this context. Our analysis indicates that (dis)similarities of propensity scales between different regions of the Ramachandran plot are coupled with (dis)similarities in the local geometry. The concept that similarities of the propensity scales are dictated by the similarity of the NCαC angle and not necessarily by the similarity of the (φ, ψ) conformation may have far-reaching implications in the field.
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9
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Zhang L, Kang H, Perez-Aguilar JM, Zhou R. Possible Co-Evolution of Polyglutamine and Polyproline in Huntingtin Protein: Proline-Rich Domain as Transient Folding Chaperone. J Phys Chem Lett 2022; 13:6331-6341. [PMID: 35796410 DOI: 10.1021/acs.jpclett.2c01184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Huntington's disease is an inherited neurodegenerative disorder caused by the overduplication of CAG repeats in the Huntingtin gene. Recent findings revealed that among the orthologs, the expansion of CAG repeats (polyQ) in the Huntingtin gene occurs in tandem with the duplication of CCG repeats (polyP). However, the molecular mechanism of this possible co-evolution remains unknown. We examined the structures of Huntingtin exon 1 (HttEx1) from six species along with five designed mutants. We found that the polyP segments "chaperone" the rest of the HttEx1 by forming ad hoc polyP binding grooves. Such a process elongates the otherwise poorly solvated polyQ domain, while modulating its secondary structure propensity from β-strands to α-helices. This chaperoning effect is achieved mostly through transient hydrogen bond interactions between polyP and the rest of HttEx1, resulting in a striking golden ratio of ∼2:1 between the chain lengths of polyQ and polyP.
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Affiliation(s)
- Leili Zhang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Hongsuk Kang
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
| | - Jose Manuel Perez-Aguilar
- School of Chemical Sciences, Meritorious Autonomous University of Puebla (BUAP), University City, Puebla 72570, Mexico
| | - Ruhong Zhou
- Computational Biology Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598, United States
- Institute of Quantitative Biology, College of Life Sciences, Zhejiang University, Hangzhou 310027, China
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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10
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The Effects of Charged Amino Acid Side-Chain Length on Diagonal Cross-Strand Interactions between Carboxylate- and Ammonium-Containing Residues in a β-Hairpin. Molecules 2022; 27:molecules27134172. [PMID: 35807421 PMCID: PMC9268152 DOI: 10.3390/molecules27134172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 02/02/2023] Open
Abstract
The β-sheet is one of the common protein secondary structures, and the aberrant aggregation of β-sheets is implicated in various neurodegenerative diseases. Cross-strand interactions are an important determinant of β-sheet stability. Accordingly, both diagonal and lateral cross-strand interactions have been studied. Surprisingly, diagonal cross-strand ion-pairing interactions have yet to be investigated. Herein, we present a systematic study on the effects of charged amino acid side-chain length on a diagonal ion-pairing interaction between carboxylate- and ammonium-containing residues in a β-hairpin. To this end, 2D-NMR was used to investigate the conformation of the peptides. The fraction folded population and the folding free energy were derived from the chemical shift data. The fraction folded population for these peptides with potential diagonal ion pairs was mostly lower compared to the corresponding peptide with a potential lateral ion pair. The diagonal ion-pairing interaction energy was derived using double mutant cycle analysis. The Asp2-Dab9 (Asp: one methylene; Dab: two methylenes) interaction was the most stabilizing (−0.79 ± 0.14 kcal/mol), most likely representing an optimal balance between the entropic penalty to enable the ion-pairing interaction and the number of side-chain conformations that can accommodate the interaction. These results should be useful for designing β-sheet containing molecular entities for various applications.
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11
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Brom JA, Pielak GJ. Desiccation‐tolerance and globular proteins adsorb similar amounts of water. Protein Sci 2022; 31:e4288. [PMID: 35481639 PMCID: PMC8994485 DOI: 10.1002/pro.4288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 11/11/2022]
Abstract
When exposed to desiccation stress, extremotolerant organisms from all domains of life produce protective disordered proteins with the potential to inform the design of excipients for formulating biologics and industrial enzymes. However, the mechanism(s) of desiccation protection remain largely unknown. To investigate the role of water sorption in desiccation protection, we use thermogravimetric analysis to study water adsorption by two desiccation-tolerance proteins, cytosolic abundant heat soluble protein D from tardigrades and late embryogenesis abundant protein 4 from the anhydrobiotic midge Polypedilum vanderplanki, and, as a control, the globular B1 domain of staphylococcal protein G. All samples adsorb similar amounts of water, suggesting that modulated water retention is not responsible for dehydration protection by desiccation-tolerance proteins.
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Affiliation(s)
- Julia A. Brom
- Department of Chemistry University of North Carolina at Chapel Hill (UNC‐CH) Chapel Hill North Carolina USA
| | - Gary J. Pielak
- Department of Chemistry University of North Carolina at Chapel Hill (UNC‐CH) Chapel Hill North Carolina USA
- Department of Biochemistry and Biophysics University of North Carolina at Chapel Hill (UNC‐CH) Chapel Hill North Carolina USA
- Lineberger Cancer Center University of North Carolina at Chapel Hill (UNC‐CH) Chapel Hill North Carolina USA
- Integrative Program for Biological and Genome Sciences University of North Carolina at Chapel Hill (UNC‐CH) Chapel Hill North Carolina USA
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12
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Crilly CJ, Brom JA, Warmuth O, Esterly HJ, Pielak GJ. Protection by desiccation-tolerance proteins probed at the residue level. Protein Sci 2022; 31:396-406. [PMID: 34766407 PMCID: PMC8819849 DOI: 10.1002/pro.4231] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 02/03/2023]
Abstract
Extremotolerant organisms from all domains of life produce protective intrinsically disordered proteins (IDPs) in response to desiccation stress. In vitro, many of these IDPs protect enzymes from dehydration stress better than U.S. Food and Drug Administration-approved excipients. However, as with most excipients, their protective mechanism is poorly understood. Here, we apply thermogravimetric analysis, differential scanning calorimetry, and liquid-observed vapor exchange (LOVE) NMR to study the protection of two model globular proteins (the B1 domain of staphylococcal protein G [GB1] and chymotrypsin inhibitor 2 [CI2]) by two desiccation-tolerance proteins (CAHS D from tardigrades and PvLEA4 from an anhydrobiotic midge), as well as by disordered and globular protein controls. We find that all protein samples retain similar amounts of water and possess similar glass transition temperatures, suggesting that neither enhanced water retention nor vitrification is responsible for protection. LOVE NMR reveals that IDPs protect against dehydration-induced unfolding better than the globular protein control, generally protect the same regions of GB1 and CI2, and protect GB1 better than CI2. These observations suggest that electrostatic interactions, charge patterning, and expanded conformations are key to protection. Further application of LOVE NMR to additional client proteins and protectants will deepen our understanding of dehydration protection, enabling the streamlined production of dehydrated proteins for expanded use in the medical, biotechnology, and chemical industries.
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Affiliation(s)
- Candice J. Crilly
- Department of ChemistryUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA
| | - Julia A. Brom
- Department of ChemistryUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA
| | - Owen Warmuth
- Department of ChemistryUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA
| | - Harrison J. Esterly
- Department of ChemistryUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA
| | - Gary J. Pielak
- Department of ChemistryUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA,Department of Biochemistry & BiophysicsUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA,Lineberger Cancer CenterUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA,Integrative Program for Biological and Genome SciencesUniversity of North Carolina at Chapel Hill (UNC‐CH)Chapel HillNorth CarolinaUSA
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13
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Rundell S, Munyaradzi O, Bong D. Enhanced Triplex Hybridization of DNA and RNA via Syndiotactic Side Chain Presentation in Minimal bPNAs. Biochemistry 2021; 61:85-91. [PMID: 34955016 DOI: 10.1021/acs.biochem.1c00693] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
General design principles for recognition at noncanonical interfaces of DNA and RNA remain elusive. Triplex hybridization of bifacial peptide nucleic acids (bPNAs) with oligo-T/U DNAs and RNAs is a robust recognition platform that can be used to define structure-function relationships in synthetic triplex formation. To this end, a set of minimal (mw < 1 kD) bPNA variants was synthesized to probe the impact of amino acid secondary structural propensity, stereochemistry, and backbone cyclization on hybridization with short, unstructured T-rich DNA and U-rich RNAs. Thermodynamic parameters extracted from optical melting analyses of bPNA variant hybrids indicated that there are two bPNA backbone modifications that significantly improve hybridization: alternating (d, l) configuration in open-chain dipeptides and homochiral dipeptide cyclization to diketopiperazine. Further, binding to DNA is preferred over RNA for all bPNA variants. Thymine-uracil substitutions in DNA substrates revealed that the methyl group of thymine accounts for 71% of ΔΔGDNA-RNA for open-chain bPNAs but only 40% of ΔΔGDNA-RNA for diketopiperazine bPNA, suggesting a greater sensitivity to RNA conformation and more optimized stacking in the cyclic bPNA. Together, these data reveal pressure points for tuning triplex hybridization at the chiral centers of bPNA, backbone conformation, stacking effects at the base triple, and the nucleic acid substrate itself. A structural blueprint for enhancing bPNA targeting of both DNA and RNA substrates includes syndiotactic base presentation (as found in homochiral diketopiperazines and d, l peptides), expansion of base stacking, and further investigation of bPNA backbone preorganization.
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Affiliation(s)
- Sarah Rundell
- Department of Chemistry & Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - Oliver Munyaradzi
- Department of Chemistry & Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
| | - Dennis Bong
- Department of Chemistry & Biochemistry, The Ohio State University, 100 W. 18th Avenue, Columbus, Ohio 43210, United States
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14
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Guzzo A, Delarue P, Rojas A, Nicolaï A, Maisuradze GG, Senet P. Missense Mutations Modify the Conformational Ensemble of the α-Synuclein Monomer Which Exhibits a Two-Phase Characteristic. Front Mol Biosci 2021; 8:786123. [PMID: 34912851 PMCID: PMC8667727 DOI: 10.3389/fmolb.2021.786123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/25/2021] [Indexed: 12/15/2022] Open
Abstract
α-Synuclein is an intrinsically disordered protein occurring in different conformations and prone to aggregate in β-sheet structures, which are the hallmark of the Parkinson disease. Missense mutations are associated with familial forms of this neuropathy. How these single amino-acid substitutions modify the conformations of wild-type α-synuclein is unclear. Here, using coarse-grained molecular dynamics simulations, we sampled the conformational space of the wild type and mutants (A30P, A53P, and E46K) of α-synuclein monomers for an effective time scale of 29.7 ms. To characterize the structures, we developed an algorithm, CUTABI (CUrvature and Torsion based of Alpha-helix and Beta-sheet Identification), to identify residues in the α-helix and β-sheet from Cα-coordinates. CUTABI was built from the results of the analysis of 14,652 selected protein structures using the Dictionary of Secondary Structure of Proteins (DSSP) algorithm. DSSP results are reproduced with 93% of success for 10 times lower computational cost. A two-dimensional probability density map of α-synuclein as a function of the number of residues in the α-helix and β-sheet is computed for wild-type and mutated proteins from molecular dynamics trajectories. The density of conformational states reveals a two-phase characteristic with a homogeneous phase (state B, β-sheets) and a heterogeneous phase (state HB, mixture of α-helices and β-sheets). The B state represents 40% of the conformations for the wild-type, A30P, and E46K and only 25% for A53T. The density of conformational states of the B state for A53T and A30P mutants differs from the wild-type one. In addition, the mutant A53T has a larger propensity to form helices than the others. These findings indicate that the equilibrium between the different conformations of the α-synuclein monomer is modified by the missense mutations in a subtle way. The α-helix and β-sheet contents are promising order parameters for intrinsically disordered proteins, whereas other structural properties such as average gyration radius, Rg, or probability distribution of Rg cannot discriminate significantly the conformational ensembles of the wild type and mutants. When separated in states B and HB, the distributions of Rg are more significantly different, indicating that global structural parameters alone are insufficient to characterize the conformational ensembles of the α-synuclein monomer.
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Affiliation(s)
- Adrien Guzzo
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Patrice Delarue
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Ana Rojas
- Schrödinger, Inc., New York, NY, United States
| | - Adrien Nicolaï
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France
| | - Gia G Maisuradze
- Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
| | - Patrick Senet
- Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Université de Bourgogne Franche-Comté, Dijon, France.,Baker Laboratory of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, United States
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15
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Hadianamrei R, Tomeh MA, Brown S, Wang J, Zhao X. Correlation between the secondary structure and surface activity of β-sheet forming cationic amphiphilic peptides and their anticancer activity. Colloids Surf B Biointerfaces 2021; 209:112165. [PMID: 34715505 DOI: 10.1016/j.colsurfb.2021.112165] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/07/2021] [Accepted: 10/16/2021] [Indexed: 01/01/2023]
Abstract
Cancer is one of the main causes of death worldwide. The current cancer treatment strategies often lack selectivity for cancer cells resulting in dose-limiting adverse effects and reduced quality of life. Recently, anticancer peptides (ACPs) have emerged as an alternative treatment with higher selectivity, less adverse effects, and lower propensity for drug resistance. However, most of the current studies on the ACPs are focused on α-helical ACPs and there is lack of systematic studies on β-sheet forming ACPs. Herein we report the development of a new series of rationally designed short cationic amphiphilic β-sheet forming ACPs and their structure activity relationship. The peptides had the general formula (XY1XY2)3, with X representing hydrophobic amino acids (isoleucine (I) or leucine (L)), Y1 and Y2 representing cationic amino acids (arginine (R) or lysine (K)). The cytotoxicity of the designed ACPs in HCT 116 colorectal cancer, HeLa cervical cancer and human dermal fibroblast (HDF) cells was assessed by MTT test. The physicochemical properties of the peptides were characterized by various techniques including RP-HPLC, LC-MS, and Circular Dichroism (CD) spectroscopy. The surface activity of the peptides at the air-water interface and their interaction with the lipid monolayers as models for cell membranes were studied by Langmuir trough. The peptides consisting of I with R and K had selective anticancer activity while the combination of L and R diminished the anticancer activity of the peptides but rendered them more toxic to HDFs. The anticancer activity of the peptides was directed by their surface activity (amphiphilicity) and their secondary structure in hydrophobic surfaces including cancer cell membranes. The selectivity of the peptides for cancer cells was a result of their higher penetration into cancer cell membranes compared to normal cell membranes. The peptides exerted their anticancer activity by disrupting the mitochondrial membranes and eventually apoptosis. The results presented in this study provide an insight into the structure-activity relationship of this class of ACPs which can be employed as guidance to design new ACPs with improved anticancer activity and lower toxicity against normal cells.
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Affiliation(s)
- Roja Hadianamrei
- Department of Chemical and Biological Engineering, University of Sheffield, S1 3JD, UK
| | - Mhd Anas Tomeh
- Department of Chemical and Biological Engineering, University of Sheffield, S1 3JD, UK
| | - Stephen Brown
- Department of Biomedical Science, University of Sheffield, S10 2TN, UK
| | - Jiqian Wang
- Centre for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266555, China
| | - Xiubo Zhao
- Department of Chemical and Biological Engineering, University of Sheffield, S1 3JD, UK; School of Pharmacy, Changzhou University, Changzhou 213164, China.
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16
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Crilly CJ, Eicher JE, Warmuth O, Atkin JM, Pielak GJ. Water's Variable Role in Protein Stability Uncovered by Liquid-Observed Vapor Exchange NMR. Biochemistry 2021; 60:3041-3045. [PMID: 34596383 DOI: 10.1021/acs.biochem.1c00552] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Water is essential to protein structure and stability, yet our understanding of how water shapes proteins is far from thorough. Our incomplete knowledge of protein-water interactions is due in part to a long-standing technological inability to assess experimentally how water removal impacts local protein structure. It is now possible to obtain residue-level information on dehydrated protein structures via liquid-observed vapor exchange (LOVE) NMR, a solution NMR technique that quantifies the extent of hydrogen-deuterium exchange between unprotected amide protons of a dehydrated protein and D2O vapor. Here, we apply LOVE NMR, Fourier transform infrared spectroscopy, and solution hydrogen-deuterium exchange to globular proteins GB1, CI2, and two variants thereof to link mutation-induced changes in the dehydrated protein structure to changes in solution structure and stability. We find that a mutation that destabilizes GB1 in solution does not affect its dehydrated structure, whereas a mutation that stabilizes CI2 in solution makes several regions of the protein more susceptible to dehydration-induced unfolding, suggesting that water is primarily responsible for the destabilization of the GB1 variant but plays a stabilizing role in the CI2 variant. Our results indicate that changes in dehydrated protein structure cannot be predicted from changes in solution stability alone and demonstrate the ability of LOVE NMR to uncover the variable role of water in protein stability. Further application of LOVE NMR to other proteins and their variants will improve the ability to predict and modulate protein structure and stability in both the hydrated and dehydrated states for applications in medicine and biotechnology.
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Affiliation(s)
- Candice J Crilly
- Department of Chemistry, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, North Carolina 27599-3290, United States
| | - Jonathan E Eicher
- Department of Chemistry, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, North Carolina 27599-3290, United States
| | - Owen Warmuth
- Department of Chemistry, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, North Carolina 27599-3290, United States
| | - Joanna M Atkin
- Department of Chemistry, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, North Carolina 27599-3290, United States
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, North Carolina 27599-3290, United States.,Department of Biochemistry & Biophysics, UNC-CH, Chapel Hill, North Carolina 27599, United States.,Lineberger Cancer Center, UNC-CH, Chapel Hill, North Carolina 27599, United States.,Integrative Program for Biological and Genome Sciences, UNC-CH, Chapel Hill, North Carolina 27599, United States
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17
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Richaud AD, Zhao G, Hobloss S, Roche SP. Folding in Place: Design of β-Strap Motifs to Stabilize the Folding of Hairpins with Long Loops. J Org Chem 2021; 86:13535-13547. [PMID: 34499510 PMCID: PMC8576641 DOI: 10.1021/acs.joc.1c01442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite their pivotal role in defining antibody affinity and protein function, β-hairpins harboring long noncanonical loops remain synthetically challenging because of the large entropic penalty associated with their conformational folding. Little is known about the contribution and impact of stabilizing motifs on the folding of β-hairpins with loops of variable length and plasticity. Here, we report a design of minimalist β-straps (strap = strand + cap) that offset the entropic cost of long-loop folding. The judicious positioning of noncovalent interactions (hydrophobic cluster and salt-bridge) within the novel 8-mer β-strap design RW(V/H)W···WVWE stabilizes hairpins with up to 10-residue loops of varying degrees of plasticity (Tm up to 52 °C; 88 ± 1% folded at 18 °C). This "hyper" thermostable β-strap outperforms the previous gold-standard technology of β-strand-β-cap (16-mer) and provides a foundation for producing new classes of long hairpins as a viable and practical alternative to macrocyclic peptides.
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Affiliation(s)
- Alexis D Richaud
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Guangkuan Zhao
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Samir Hobloss
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
| | - Stéphane P Roche
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, Florida 33431, United States
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18
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Menard LM, Wood NB, Vigoreaux JO. Secondary Structure of the Novel Myosin Binding Domain WYR and Implications within Myosin Structure. BIOLOGY 2021; 10:603. [PMID: 34209926 PMCID: PMC8301185 DOI: 10.3390/biology10070603] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 06/25/2021] [Accepted: 06/27/2021] [Indexed: 01/05/2023]
Abstract
Structural changes in the myosin II light meromyosin (LMM) that influence thick filament mechanical properties and muscle function are modulated by LMM-binding proteins. Flightin is an LMM-binding protein indispensable for the function of Drosophila indirect flight muscle (IFM). Flightin has a three-domain structure that includes WYR, a novel 52 aa domain conserved throughout Pancrustacea. In this study, we (i) test the hypothesis that WYR binds the LMM, (ii) characterize the secondary structure of WYR, and (iii) examine the structural impact WYR has on the LMM. Circular dichroism at 260-190 nm reveals a structural profile for WYR and supports an interaction between WYR and LMM. A WYR-LMM interaction is supported by co-sedimentation with a stoichiometry of ~2.4:1. The WYR-LMM interaction results in an overall increased coiled-coil content, while curtailing ɑ helical content. WYR is found to be composed of 15% turns, 31% antiparallel β, and 48% 'other' content. We propose a structural model of WYR consisting of an antiparallel β hairpin between Q92-K114 centered on an ASX or β turn around N102, with a G1 bulge at G117. The Drosophila LMM segment used, V1346-I1941, encompassing conserved skip residues 2-4, is found to possess a traditional helical profile but is interpreted as having <30% helical content by multiple methods of deconvolution. This low helicity may be affiliated with the dynamic behavior of the structure in solution or the inclusion of a known non-helical region in the C-terminus. Our results support the hypothesis that WYR binds the LMM and that this interaction brings about structural changes in the coiled-coil. These studies implicate flightin, via the WYR domain, for distinct shifts in LMM secondary structure that could influence the structural properties and stabilization of the thick filament, scaling to modulation of whole muscle function.
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Affiliation(s)
| | | | - Jim O. Vigoreaux
- Department of Biology, University of Vermont, Burlington, VT 05405, USA; (L.M.M.); (N.B.W.)
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19
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Chang JY, Li NZ, Wang WM, Liu CT, Yu CH, Chen YC, Lu D, Lin PH, Huang CH, Kono O, Yang TY, Sun YT, Huang PY, Pan YJ, Chen TH, Liu MC, Huang SL, Huang SJ, Cheng RP. Longer charged amino acids favor β-strand formation in hairpin peptides. J Pept Sci 2021; 27:e3333. [PMID: 34114290 DOI: 10.1002/psc.3333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 04/08/2021] [Accepted: 04/13/2021] [Indexed: 11/11/2022]
Abstract
Interactions between charged amino acids significantly influence the structure and function of proteins. The encoded charged amino acids Asp, Glu, Arg, and Lys have different number of hydrophobic methylenes linking the backbone to the charged functionality. It remains to be fully understood how does this difference in the number of methylenes affect protein structure stability. Protein secondary structures are the fundamental three-dimensional building blocks of protein structures. β-Sheet structures are particularly interesting, because these structures have been associated with a number of protein misfolding diseases. Herein, we report the effect of charged amino acid side chain length at two β-strand positions individually on the stability of a β-hairpin. The charged amino acids include side chains with a carboxylate, an ammonium, or a guanidinium group. The experimental peptides, fully folded reference peptides, and fully unfolded reference peptides were synthesized by solid phase peptide synthesis and analyzed by 2D NMR methods including TOCSY, DQF-COSY, and ROESY. Sequence specific assignments were performed for all peptides. The chemical shift data were used to derive the fraction folded population and the folding free energy for the experimental peptides. Results showed that the fraction folded population increased with increasing charged amino acid side chain length. These results should be useful for developing functional peptides that adopt the β-conformation.
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Affiliation(s)
- Jing-Yuan Chang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Nian-Zhi Li
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Wei-Ming Wang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Chih-Ting Liu
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Chen-Hsu Yu
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Yan-Chen Chen
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Daniel Lu
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Pei-Hsuan Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Cheng-Hsin Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Orika Kono
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Tzu-Yi Yang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Yi-Ting Sun
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Pei-Yu Huang
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Yen-Jin Pan
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Ting-Hsuan Chen
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Mu-Chun Liu
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
| | - Shou-Ling Huang
- Instrumentation Center, National Taiwan University, Taipei, Taiwan
| | - Shing-Jong Huang
- Instrumentation Center, National Taiwan University, Taipei, Taiwan
| | - Richard P Cheng
- Department of Chemistry, National Taiwan University, Taipei, Taiwan
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20
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Jia Bu Y, Nitz M. Incorporation of TePhe into Expressed Proteins is Minimally Perturbing. Chembiochem 2021; 22:2449-2456. [PMID: 34003548 DOI: 10.1002/cbic.202100160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 05/14/2021] [Indexed: 01/24/2023]
Abstract
Tellurium is a versatile heavy chalcogen with numerous applications in chemical biology, providing valuable probes in mass cytometry, fluorescence imaging and structural biology. L-Tellurienylalanine (TePhe) is an analogue of the proteinogenic amino acid L-phenylalanine (Phe) in which the phenyl side chain has been replaced by a 5-membered tellurophene moiety. High incorporation level of TePhe in expressed proteins at defined sites is expected to facilitate studies in proteomics, protein NMR spectroscopy, and structure elucidation. As a model we chose immunoglobulin-binding Protein G, B1 domain (GB1) to validate TePhe as a suitable structural analogue for Phe. We demonstrate that approximately 1 in 2 of all Phe sites within GB1 can be substituted with TePhe through expression in standard non-Phe-auxotrophic E. coli in Phe-deficient media containing glyphosate, an inhibitor of aromatic amino acid biosynthesis. The TePhe content of the GB1 sample can be further increased to 85 % through HPLC. Using NMR and CD spectroscopy, we confirm that the Phe-to-TePhe substitution has negligible impact on the global structure and stability of GB1.
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Affiliation(s)
- Yong Jia Bu
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
| | - Mark Nitz
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, M5S 3H6, Canada
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21
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Speer SL, Zheng W, Jiang X, Chu IT, Guseman AJ, Liu M, Pielak GJ, Li C. The intracellular environment affects protein-protein interactions. Proc Natl Acad Sci U S A 2021; 118:e2019918118. [PMID: 33836588 PMCID: PMC7980425 DOI: 10.1073/pnas.2019918118] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Protein-protein interactions are essential for life but rarely thermodynamically quantified in living cells. In vitro efforts show that protein complex stability is modulated by high concentrations of cosolutes, including synthetic polymers, proteins, and cell lysates via a combination of hard-core repulsions and chemical interactions. We quantified the stability of a model protein complex, the A34F GB1 homodimer, in buffer, Escherichia coli cells and Xenopus laevis oocytes. The complex is more stable in cells than in buffer and more stable in oocytes than E. coli Studies of several variants show that increasing the negative charge on the homodimer surface increases stability in cells. These data, taken together with the fact that oocytes are less crowded than E. coli cells, lead to the conclusion that chemical interactions are more important than hard-core repulsions under physiological conditions, a conclusion also gleaned from studies of protein stability in cells. Our studies have implications for understanding how promiscuous-and specific-interactions coherently evolve for a protein to properly function in the crowded cellular environment.
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Affiliation(s)
- Shannon L Speer
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Wenwen Zheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071 Wuhan, China
- Graduate University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xin Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071 Wuhan, China
- Graduate University of Chinese Academy of Sciences, 100049 Beijing, China
| | - I-Te Chu
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Alex J Guseman
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071 Wuhan, China
| | - Gary J Pielak
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599;
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599
- Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan National Laboratory for Optoelectronics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, 430071 Wuhan, China;
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22
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Crilly CJ, Brom JA, Kowalewski ME, Piszkiewicz S, Pielak GJ. Dried Protein Structure Revealed at the Residue Level by Liquid-Observed Vapor Exchange NMR. Biochemistry 2021; 60:152-159. [PMID: 33400518 DOI: 10.1021/acs.biochem.0c00863] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Water is key to protein structure and stability, yet the relationship between protein-water interactions and structure is poorly understood, in part because there are few techniques that permit the study of dehydrated protein structure at high resolution. Here, we describe liquid-observed vapor exchange (LOVE) NMR, a solution NMR-based method that provides residue-level information about the structure of dehydrated proteins. Using the model protein GB1, we show that LOVE NMR measurements reflect the fraction of the dried protein population trapped in a conformation where a given residue is protected from exchange with D2O vapor. Comparisons to solution hydrogen-deuterium exchange data affirm that the dried protein structure is strongly influenced by local solution stability and that the mechanism of dehydration protection exerted by the widely used protectant trehalose differs from its mechanism of stabilization in solution. Our results highlight the need for refined models of cosolute-mediated dehydration protection and demonstrate the ability of LOVE NMR to inform such models.
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Affiliation(s)
- Candice J Crilly
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Julia A Brom
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Mark E Kowalewski
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Samantha Piszkiewicz
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Gary J Pielak
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States.,Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Lineberger Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States.,Integrative Program for Biological & Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7100, United States
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23
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Chan NJA, Gu D, Tan S, Fu Q, Pattison TG, O'Connor AJ, Qiao GG. Spider-silk inspired polymeric networks by harnessing the mechanical potential of β-sheets through network guided assembly. Nat Commun 2020; 11:1630. [PMID: 32242004 PMCID: PMC7118121 DOI: 10.1038/s41467-020-15312-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 02/24/2020] [Indexed: 12/26/2022] Open
Abstract
The high toughness of natural spider-silk is attributed to their unique β-sheet secondary structures. However, the preparation of mechanically strong β-sheet rich materials remains a significant challenge due to challenges involved in processing the polymers/proteins, and managing the assembly of the hydrophobic residues. Inspired by spider-silk, our approach effectively utilizes the superior mechanical toughness and stability afforded by localised β-sheet domains within an amorphous network. Using a grafting-from polymerisation approach within an amorphous hydrophilic network allows for spatially controlled growth of poly(valine) and poly(valine-r-glycine) as β-sheet forming polypeptides via N-carboxyanhydride ring opening polymerisation. The resulting continuous β-sheet nanocrystal network exhibits improved compressive strength and stiffness over the initial network lacking β-sheets of up to 30 MPa (300 times greater than the initial network) and 6 MPa (100 times greater than the initial network) respectively. The network demonstrates improved resistance to strong acid, base and protein denaturants over 28 days. It is known the β-sheet structures in silk-inspired materials generate increased mechanical properties. Here, the authors report on a method of creating silk-inspired materials using in situ formation of β-sheets in an amorphous polymer to replicate the structure of silk and increase the mechanical properties.
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Affiliation(s)
- Nicholas Jun-An Chan
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Dunyin Gu
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Shereen Tan
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Qiang Fu
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Thomas Geoffrey Pattison
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Andrea J O'Connor
- Department of Biomedical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia
| | - Greg G Qiao
- Polymer Science Group, Department of Chemical Engineering, University of Melbourne, Parkville, Melbourne, VIC, 3010, Australia.
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24
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Urmey AR, Zondlo NJ. Structural preferences of cysteine sulfinic acid: The sulfinate engages in multiple local interactions with the peptide backbone. Free Radic Biol Med 2020; 148:96-107. [PMID: 31883974 DOI: 10.1016/j.freeradbiomed.2019.12.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/16/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023]
Abstract
Cysteine sulfinic acid (Cys-SO2-) is a non-enzymatic oxidative post-translational modification (PTM) that has been identified in hundreds of proteins. However, the effects of cysteine sulfination are in most cases poorly understood. Cys-SO2- is structurally distinctive, with long sulfur-carbon and sulfur-oxygen bonds, and with tetrahedral geometry around sulfur due to its lone pair. Cys-SO2- thus has a unique range of potential interactions with the protein backbone which could facilitate protein structural changes. Herein, the structural effects of cysteine oxidation to the sulfinic acid were investigated in model peptides and folded proteins using NMR spectroscopy, circular dichroism, bioinformatics, and computational studies. In the PDB, Cys-SO2- shows a greater preference for α-helix than Cys. In addition, Cys-SO2- is more commonly found in structures with φ > 0, including in multiple types of β-turn. Sulfinate oxygens engage in hydrogen bonds with adjacent (i or i + 1) amide hydrogens. Over half of sulfinates have at least one hydrogen bond with an adjacent amide, and several structures have hydrogen bonds with both adjacent amides. Alternately, sulfur or either oxygen can act as an electron donor for n→π* interactions with the backbone carbonyl of the same residue, as indicated by frequent S⋯CO or O⋯CO distances below the sums of their van der Waals radii in protein structures. In peptides, Cys-SO2- favored α-helical structure at the N-terminus, consistent with helix dipole effects and backbone hydrogen bonds with the sulfinate promoting α-helix. Cys-SO2- has only modestly greater polyproline II helix propensity than Cys-SH, likely due to competition from multiple side chain-backbone interactions. Cys-SO2- stabilizes the i+1 position of a β-turn relative to Cys-SH. Within proteins, the range of side chain-main chain interactions available to Cys-SO2- compared to Cys-SH provides a basis for potential changes in protein structure and function due to cysteine oxidation to the sulfinic acid.
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Affiliation(s)
- Andrew R Urmey
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States
| | - Neal J Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE, 19716, United States.
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25
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Centore R, Totsingan F, Amason AC, Lyons S, Zha RH, Gross RA. Self-Assembly-Assisted Kinetically Controlled Papain-Catalyzed Formation of mPEG- b-Phe(Leu) x. Biomacromolecules 2020; 21:493-507. [PMID: 31820938 DOI: 10.1021/acs.biomac.9b01237] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Self-assembling peptide materials are promising next-generation materials with applications that include tissue engineering scaffolds, drug delivery, bionanomedicine, and enviro-responsive materials. Despite these advances, synthetic methods to form peptides and peptide-polymer conjugates still largely rely on solid-phase peptide synthesis (SPPS) and N-carboxyanhydride ring-opening polymerization (NCA-ROP), while green methods remain largely undeveloped. This work demonstrates a protease-catalyzed peptide synthesis (PCPS) capable of directly grafting leucine ethyl ester (Leu-OEt) from the C-terminus of a methoxy poly(ethylene glycol)-phenylalanine ethyl ester macroinitiator in a one-pot, aqueous reaction. By using the natural tendency of the growing hydrophobic peptide segment to self-assemble, a large narrowing of the (Leu)x distributions for both mPEG45-b-Phe(Leu)x and oligo(Leu)x coproducts, relative to oligo(Leu)x synthesized in the absence of a macroinitiator (mPEG45-Phe-OEt), was achieved. A mechanism is described where in situ β-sheet coassembly of mPEG45-b-Phe(Leu)x and oligo(Leu)x coproducts during polymerization prevents peptide hydrolysis, providing a means to control the degree of polymerization (DP) and dispersity of diblock (Leu)x segments (matrix-assisted laser desorption time-of-flight (MALDI-TOF) x = 5.1, dispersity ≤ 1.02). The use of self-assembly to control the uniformity of peptides synthesized by PCPS paves the way for precise peptide block copolymer architectures with various polymer backbones and amino acid compositions synthesized by a green process.
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26
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Chen Q, Xu S, Lu X, Boeri MV, Pepelyayeva Y, Diaz EL, Soni SD, Allaire M, Forstner MB, Bahnson BJ, Rozovsky S. 77Se NMR Probes the Protein Environment of Selenomethionine. J Phys Chem B 2020; 124:601-616. [PMID: 31846581 DOI: 10.1021/acs.jpcb.9b07466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulfur is critical for the correct structure and proper function of proteins. Yet, lacking a sensitive enough isotope, nuclear magnetic resonance (NMR) experiments are unable to deliver for sulfur in proteins the usual wealth of chemical, dynamic, and structural information. This limitation can be circumvented by substituting sulfur with selenium, which has similar physicochemical properties and minimal impact on protein structures but possesses an NMR compatible isotope (77Se). Here we exploit the sensitivity of 77Se NMR to the nucleus' chemical milieu and use selenomethionine as a probe for its proteinaceous environment. However, such selenium NMR spectra of proteins currently resist a reliable interpretation because systematic connections between variations of system variables and changes in 77Se NMR parameters are still lacking. To start narrowing this knowledge gap, we report here on a biological 77Se magnetic resonance data bank based on a systematically designed library of GB1 variants in which a single selenomethionine was introduced at different locations within the protein. We recorded the resulting isotropic 77Se chemical shifts and relaxation times for six GB1 variants by solution-state 77Se NMR. For four of the GB1 variants we were also able to determine the chemical shift anisotropy tensor of SeM by solid-state 77Se NMR. To enable interpretation of the NMR data, the structures of five of the GB1 variants were solved by X-ray crystallography to a resolution of 1.2 Å, allowing us to unambiguously determine the conformation of the selenomethionine. Finally, we combine our solution- and solid-state NMR data with the structural information to arrive at general insights regarding the execution and interpretation of 77Se NMR experiments that exploit selenomethionine to probe proteins.
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Affiliation(s)
- Qingqing Chen
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Shiping Xu
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Xingyu Lu
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Instrumentation and Service Center for Physical Sciences , Westlake University , Hangzhou , Zhejiang 310024 , China
| | - Michael V Boeri
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Neuroscience Department, Medical Toxicology Research Division , U.S. Army Medical Research Institute of Chemical Defense , 8350 Ricketts Point Road , Gunpowder , Maryland 21010 , United States
| | - Yuliya Pepelyayeva
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States.,Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine , Michigan State University , East Lansing , Michigan 48824 , United States
| | - Elizabeth L Diaz
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Sunil-Datta Soni
- Neuroscience Department, Medical Toxicology Research Division , U.S. Army Medical Research Institute of Chemical Defense , 8350 Ricketts Point Road , Gunpowder , Maryland 21010 , United States
| | - Marc Allaire
- Berkeley Center for Structural Biology, Molecular Biophysics & Integrated Bioimaging , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Martin B Forstner
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Brian J Bahnson
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
| | - Sharon Rozovsky
- Department of Chemistry and Biochemistry , University of Delaware , Newark , Delaware 19716 , United States
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27
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Atypical structural tendencies among low-complexity domains in the Protein Data Bank proteome. PLoS Comput Biol 2020; 16:e1007487. [PMID: 31986130 PMCID: PMC7004392 DOI: 10.1371/journal.pcbi.1007487] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/06/2020] [Accepted: 12/23/2019] [Indexed: 11/29/2022] Open
Abstract
A variety of studies have suggested that low-complexity domains (LCDs) tend to be intrinsically disordered and are relatively rare within structured proteins in the Protein Data Bank (PDB). Although LCDs are often treated as a single class, we previously found that LCDs enriched in different amino acids can exhibit substantial differences in protein metabolism and function. Therefore, we wondered whether the structural conformations of LCDs are likewise dependent on which specific amino acids are enriched within each LCD. Here, we directly examined relationships between enrichment of individual amino acids and secondary structure tendencies across the entire PDB proteome. Secondary structure tendencies varied as a function of the identity of the amino acid enriched and its degree of enrichment. Furthermore, divergence in secondary structure profiles often occurred for LCDs enriched in physicochemically similar amino acids (e.g. valine vs. leucine), indicating that LCDs composed of related amino acids can have distinct secondary structure tendencies. Comparison of LCD secondary structure tendencies with numerous pre-existing secondary structure propensity scales resulted in relatively poor correlations for certain types of LCDs, indicating that these scales may not capture secondary structure tendencies as sequence complexity decreases. Collectively, these observations provide a highly resolved view of structural tendencies among LCDs parsed by the nature and magnitude of single amino acid enrichment. The structures that proteins adopt are directly related to their amino acid sequences. Low-complexity domains (LCDs) in protein sequences are unusual regions made up of only a few different types of amino acids. Although this is the key feature that classifies sequences as LCDs, the physical properties of LCDs will differ based on the types of amino acids that are found in each domain. For example, the sequences “AAAAAAAAAA”, “EEEEEEEEEE”, and “EEKRKEEEKE” will have very different properties, even though they would all be classified as LCDs by traditional methods. In a previous study, we developed a new method to further divide LCDs into categories that more closely reflect the differences in their physical properties. In this study, we apply that approach to examine the structures of LCDs when sorted into different categories based on their amino acids. This allowed us to define relationships between the types of amino acids in the LCDs and their corresponding structures. Since protein structure is closely related to protein function, this has important implications for understanding the basic functions and properties of LCDs in a variety of proteins.
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28
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Albanese KI, Krone MW, Petell CJ, Parker MM, Strahl BD, Brustad EM, Waters ML. Engineered Reader Proteins for Enhanced Detection of Methylated Lysine on Histones. ACS Chem Biol 2020; 15:103-111. [PMID: 31634430 PMCID: PMC7365037 DOI: 10.1021/acschembio.9b00651] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Histone post-translational modifications (PTMs) are crucial for many cellular processes including mitosis, transcription, and DNA repair. The cellular readout of histone PTMs is dependent on both the chemical modification and histone site, and the array of histone PTMs on chromatin is dynamic throughout the eukaryotic life cycle. Accordingly, methods that report on the presence of PTMs are essential tools for resolving open questions about epigenetic processes and for developing therapeutic diagnostics. Reader domains that recognize histone PTMs have shown potential as advantageous substitutes for anti-PTM antibodies, and engineering efforts aimed at enhancing reader domain affinities would advance their efficacy as antibody alternatives. Here we describe engineered chromodomains from Drosophila melanogaster and humans that bind more tightly to H3K9 methylation (H3K9me) marks and result in the tightest reported reader-H3K9me interaction to date. Point mutations near the binding interface of the HP1 chromodomain were screened in a combinatorial fashion, and a triple mutant was found that binds 20-fold tighter than the native scaffold without any loss in PTM-site selectivity. The beneficial mutations were then translated to a human homologue, CBX1, resulting in an even tighter interaction with H3K9me3. Furthermore, we show that these engineered readers (eReaders) increase detection of H3K9me marks in several biochemical assays and outperform a commercial anti-H3K9me antibody in detecting H3K9me-containing nucleosomes in vitro, demonstrating the utility of eReaders to complement antibodies in epigenetics research.
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Affiliation(s)
- Katherine I. Albanese
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Mackenzie W. Krone
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Christopher J. Petell
- Department of Biochemistry and Biophysics, 120 Mason Farm Rd, University of North Carolina at Chapel Hill, NC, USA 27599; USA
- UNC Lineberger Comprehensive Cancer Center, 450 West Drive, University of North Carolina at Chapel Hill, NC, USA 27599; USA
| | - Madison M. Parker
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Brian D. Strahl
- Department of Biochemistry and Biophysics, 120 Mason Farm Rd, University of North Carolina at Chapel Hill, NC, USA 27599; USA
- UNC Lineberger Comprehensive Cancer Center, 450 West Drive, University of North Carolina at Chapel Hill, NC, USA 27599; USA
| | - Eric M. Brustad
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Marcey L. Waters
- Department of Chemistry, CB 3290, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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29
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Rasines Mazo A, Allison-Logan S, Karimi F, Chan NJA, Qiu W, Duan W, O’Brien-Simpson NM, Qiao GG. Ring opening polymerization of α-amino acids: advances in synthesis, architecture and applications of polypeptides and their hybrids. Chem Soc Rev 2020; 49:4737-4834. [DOI: 10.1039/c9cs00738e] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
This review provides a comprehensive overview of the latest advances in the synthesis, architectural design and biomedical applications of polypeptides and their hybrids.
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Affiliation(s)
- Alicia Rasines Mazo
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
| | - Stephanie Allison-Logan
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
| | - Fatemeh Karimi
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
| | - Nicholas Jun-An Chan
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
| | - Wenlian Qiu
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
| | - Wei Duan
- School of Medicine
- Deakin University
- Geelong
- Australia
| | - Neil M. O’Brien-Simpson
- Centre for Oral Health Research
- Melbourne Dental School and the Bio21 Institute of Molecular Science and Biotechnology
- University of Melbourne
- Parkville
- Australia
| | - Greg G. Qiao
- Polymer Science Group
- Department of Chemical Engineering
- University of Melbourne
- Parkville
- Australia
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30
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Klein T, Ulrich HF, Gruschwitz FV, Kuchenbrod MT, Takahashi R, Fujii S, Hoeppener S, Nischang I, Sakurai K, Brendel JC. Impact of amino acids on the aqueous self-assembly of benzenetrispeptides into supramolecular polymer bottlebrushes. Polym Chem 2020. [DOI: 10.1039/d0py01185a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The choice of the amino acid unit in benzenetrispeptide-PEO conjugates allows to fine-tune the self-assembly strength and to control the resulting solution morphologies in water.
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31
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Wu PY, Chen CY, Li JH, Lin JK, Chen TH, Huang SJ, Huang SL, Cheng RP. Effects of Arginine Deimination and Citrulline Side-Chain Length on Peptide Secondary Structure Formation. Chembiochem 2019; 20:2118-2124. [PMID: 31071235 DOI: 10.1002/cbic.201900231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Indexed: 01/07/2023]
Abstract
Post-translational modifications expand the chemical functionality of peptides and proteins beyond that originating from the encoded amino acids, but studies on the structural effects of these modifications have been limited. Arginine undergoes deimination to give citrulline (Cit), converting the positively charged guanidinium moiety into a neutral urea group. Herein, we report the effect of Arg deimination on secondary structure formation. To understand the reason for the number of methylene units in Cit, the effect of Cit side-chain length on secondary structure formation was also studied. Ala-based peptides and β-hairpin peptides were used to study α-helix and β-sheet formation, respectively. Peptides containing Cit analogues were prepared by an orthogonal protecting group strategy coupled with solid-phase carbamylation. The CD data for the Ala-based peptides were analyzed by using modified Lifson-Roig theory, showing that the helix propensity of Arg decreased upon deimination and that either shortening or lengthening Cit also decreased the helix propensity. The β-hairpin peptides were analyzed by NMR methods, showing minimal change in strand formation energetics upon Arg deimination. Altering the Cit side-chain length did not affect strand formation energetics either. These results should be useful for the preparation of urea-bearing systems and the design of peptides incorporating urea-bearing residues with varying side-chain length.
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Affiliation(s)
- Po-Yi Wu
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Chin-Yi Chen
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Jhe-Hao Li
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Jin-Kai Lin
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Ting-Hsuan Chen
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Shing-Jong Huang
- Instrument Center, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Shou-Ling Huang
- Instrument Center, National (Taiwan) University, Taipei, 10617, Taiwan
| | - Richard P Cheng
- Department of Chemistry, National (Taiwan) University, Taipei, 10617, Taiwan
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32
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The CDR1 and Other Regions of Immunoglobulin Light Chains are Hot Spots for Amyloid Aggregation. Sci Rep 2019; 9:3123. [PMID: 30816248 PMCID: PMC6395779 DOI: 10.1038/s41598-019-39781-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 01/17/2019] [Indexed: 12/14/2022] Open
Abstract
Immunoglobulin light chain-derived (AL) amyloidosis is a debilitating disease without known cure. Almost nothing is known about the structural factors driving the amyloidogenesis of the light chains. This study aimed to identify the fibrillogenic hotspots of the model protein 6aJL2 and in pursuing this goal, two complementary approaches were applied. One of them was based on several web-based computational tools optimized to predict fibrillogenic/aggregation-prone sequences based on different structural and biophysical properties of the polypeptide chain. Then, the predictions were confirmed with an ad-hoc synthetic peptide library. In the second approach, 6aJL2 protein was proteolyzed with trypsin, and the products incubated in aggregation-promoting conditions. Then, the aggregation-prone fragments were identified by combining standard proteomic methods, and the results validated with a set of synthetic peptides with the sequence of the tryptic fragments. Both strategies coincided to identify a fibrillogenic hotspot located at the CDR1 and β-strand C of the protein, which was confirmed by scanning proline mutagenesis analysis. However, only the proteolysis-based strategy revealed additional fibrillogenic hotspots in two other regions of the protein. It was shown that a fibrillogenic hotspot associated to the CDR1 is also encoded by several κ and λ germline variable domain gene segments. Some parts of this study have been included in the chapter “The Structural Determinants of the Immunoglobulin Light Chain Amyloid Aggregation”, published in Physical Biology of Proteins and Peptides, Springer 2015 (ISBN 978-3-319-21687-4).
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33
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Hori Y, Fujiwara H, Fujiwara W, Makabe K. Grafting a short chameleon sequence from αB crystallin into a β-sheet scaffold protein. Proteins 2019; 87:416-424. [PMID: 30684364 DOI: 10.1002/prot.25663] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 01/17/2019] [Accepted: 01/22/2019] [Indexed: 11/08/2022]
Abstract
Many protein and peptide sequences are self-assembled into β-sheet-rich fibrous structures called amyloids. Their atomic details provide insights into fundamental knowledge related to amyloid diseases. To study the detailed structure of the amyloid, we have developed a model system that mimics the self-assembling process of the amyloid within a water-soluble protein, termed peptide self-assembly mimic (PSAM). PSAM enables capturing of a peptide sequence within a water-soluble protein, thus making structural and energetics-related studies possible. In this work, we extend our PSAM approach to a naturally occurring chameleon sequence from αB crystallin. We chose "Val-Leu-Gly-Asp-Val (VLGDV)", a five amino-acid sequence, which forms a β-turn in the native structure and a β-barrel in the amyloid oligomer cylindrin, as a grafting sequence to the PSAM scaffold. The crystal structure revealed that the sequence grafting induced β-sheet bending at the grafted site. We further investigated the role of the central glycine residue and found that its role in the β-sheet bending is dependent on the neighboring residues. The ability of PSAM to observe the structural alterations induced by the grafted sequence provides an opportunity to evaluate the structural impact of a sequence from the peptide self-assembly.
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Affiliation(s)
- Yuki Hori
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata, Japan
| | - Hideki Fujiwara
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata, Japan
| | - Wataru Fujiwara
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata, Japan
| | - Koki Makabe
- Graduate School of Science and Engineering, Yamagata University, Yonezawa, Yamagata, Japan
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34
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Design and structural characterisation of monomeric water-soluble α-helix and β-hairpin peptides: State-of-the-art. Arch Biochem Biophys 2019; 661:149-167. [DOI: 10.1016/j.abb.2018.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/06/2018] [Accepted: 11/14/2018] [Indexed: 02/06/2023]
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35
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Babii O, Afonin S, Ishchenko AY, Schober T, Negelia AO, Tolstanova GM, Garmanchuk LV, Ostapchenko LI, Komarov IV, Ulrich AS. Structure–Activity Relationships of Photoswitchable Diarylethene-Based β-Hairpin Peptides as Membranolytic Antimicrobial and Anticancer Agents. J Med Chem 2018; 61:10793-10813. [DOI: 10.1021/acs.jmedchem.8b01428] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Oleg Babii
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
| | - Sergii Afonin
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
| | - Aleksandr Yu. Ishchenko
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601 Kyiv, Ukraine
- Enamine Ltd., Vul. Chervonotkatska 78, 02066 Kyiv, Ukraine
| | - Tim Schober
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
| | - Anatoliy O. Negelia
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Ganna M. Tolstanova
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Liudmyla V. Garmanchuk
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Liudmyla I. Ostapchenko
- Institute of Biology and Medicine, Taras Shevchenko National University of Kyiv, Prosp. Hlushkova 2, 03022 Kyiv, Ukraine
| | - Igor V. Komarov
- Institute of High Technologies, Taras Shevchenko National University of Kyiv, Vul. Volodymyrska 60, 01601 Kyiv, Ukraine
- Enamine Ltd., Vul. Chervonotkatska 78, 02066 Kyiv, Ukraine
- Lumobiotics GmbH, Auerstraße 2, 76227 Karlsruhe, Germany
| | - Anne S. Ulrich
- Institute of Biological Interfaces (IBG-2), Karlsruhe Institute of Technology (KIT), POB 3640, 76021 Karlsruhe, Germany
- Institute of Organic Chemistry (IOC), Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany
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36
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Oi C, Treado JD, Levine ZA, Lim CS, Knecht KM, Xiong Y, O'Hern CS, Regan L. A threonine zipper that mediates protein-protein interactions: Structure and prediction. Protein Sci 2018; 27:1969-1977. [PMID: 30198622 PMCID: PMC6201716 DOI: 10.1002/pro.3505] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 08/31/2018] [Accepted: 09/05/2018] [Indexed: 01/31/2023]
Abstract
We present the structure of an engineered protein-protein interface between two beta barrel proteins, which is mediated by interactions between threonine (Thr) residues. This Thr zipper structure suggests that the protein interface is stabilized by close-packing of the Thr residues, with only one intermonomer hydrogen bond (H-bond) between two of the Thr residues. This Thr-rich interface provides a unique opportunity to study the behavior of Thr in the context of many other Thr residues. In previous work, we have shown that the side chain (χ1 ) dihedral angles of interface and core Thr residues can be predicted with high accuracy using a hard sphere plus stereochemical constraint (HS) model. Here, we demonstrate that in the Thr-rich local environment of the Thr zipper structure, we are able to predict the χ1 dihedral angles of most of the Thr residues. Some, however, are not well predicted by the HS model. We therefore employed explicitly solvated molecular dynamics (MD) simulations to further investigate the side chain conformations of these residues. The MD simulations illustrate the role that transient H-bonding to water, in combination with steric constraints, plays in determining the behavior of these Thr side chains. Broader Audience Statement: Protein-protein interactions are critical to life and the search for ways to disrupt adverse protein-protein interactions involved in disease is an ongoing area of drug discovery. We must better understand protein-protein interfaces, both to be able to disrupt existing ones and to engineer new ones for a variety of biotechnological applications. We have discovered and characterized an artificial Thr-rich protein-protein interface. This novel interface demonstrates a heretofore unknown property of Thr-rich surfaces: mediating protein-protein interactions.
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Affiliation(s)
- Curran Oi
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
- Integrated Graduate Program in Physical and Engineering BiologyYale UniversityNew HavenConnecticut06520
| | - John D. Treado
- Integrated Graduate Program in Physical and Engineering BiologyYale UniversityNew HavenConnecticut06520
- Department of Mechanical Engineering and Materials ScienceYale UniversityNew HavenConnecticut06520
| | - Zachary A. Levine
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
- Department of PathologyYale School of MedicineNew HavenConnecticut06520
| | - Christopher S. Lim
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
| | - Kirsten M. Knecht
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
| | - Yong Xiong
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
| | - Corey S. O'Hern
- Integrated Graduate Program in Physical and Engineering BiologyYale UniversityNew HavenConnecticut06520
- Department of Mechanical Engineering and Materials ScienceYale UniversityNew HavenConnecticut06520
- Department of PhysicsYale UniversityNew HavenConnecticut06520
- Department of Applied PhysicsYale UniversityNew HavenConnecticut06520
| | - Lynne Regan
- Department of Molecular Biophysics and BiochemistryYale UniversityNew HavenConnecticut06520
- Integrated Graduate Program in Physical and Engineering BiologyYale UniversityNew HavenConnecticut06520
- Department of ChemistryYale UniversityNew HavenConnecticut06520
- Institute of Quantitative BiologyBiochemistry and Biotechnology, Center for Synthetic and Systems Biology, School of Biological Sciences, University of Edinburgh
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37
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Okur Z, Senturk OI, Yilmaz C, Gulseren G, Mammadov B, Guler MO, Tekinay AB. Promotion of neurite outgrowth by rationally designed NGF-β binding peptide nanofibers. Biomater Sci 2018; 6:1777-1790. [PMID: 29770392 DOI: 10.1039/c8bm00311d] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Promotion of neurite outgrowth is an important limiting step for regeneration in nerve injury and depends strongly on the local expression of nerve growth factor (NGF). The rational design of bioactive materials is a promising approach for the development of novel therapeutic methods for nerve regeneration, and biomaterials capable of presenting NGF to nerve cells are especially suitable for this purpose. In this study, we show bioactive peptide amphiphile (PA) nanofibers capable of promoting neurite outgrowth by displaying high density binding epitopes for NGF. A high-affinity NGF-binding sequence was identified by phage display and combined with a beta-sheet forming motif to produce a self-assembling PA molecule. The bioactive nanofiber had higher affinity for NGF compared to control nanofibers and in vitro studies revealed that the NGF binding peptide amphiphile nanofibers (NGFB-PA nanofiber) significantly promote the neurite outgrowth of PC-12 cells. In addition, the nanofibers induced differentiation of PC-12 cells into neuron-like cells by enhancing NGF/high-activity NGF receptor (TrkA) interactions and activating MAPK pathway elements. The NGFB-PA nanofiber was further shown as a promising material to support axonal outgrowth from primary sensory neurons. These materials will pave the way for the development of new therapeutic agents for peripheral nervous system injuries.
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Affiliation(s)
- Zeynep Okur
- Institute of Materials Science and Nanotechnology and National Nanotechnology Research Center (UNAM), Bilkent University, Ankara, 06800, Turkey.
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38
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Cole AE, Hani FM, Allen BW, Kline PC, Altman E. Nonfunctional Missense Mutants in Two Well Characterized Cytosolic Enzymes Reveal Important Information About Protein Structure and Function. Protein J 2018; 37:407-427. [DOI: 10.1007/s10930-018-9786-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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39
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Maritan M, Veggi D, Cozzi R, Dello Iacono L, Bartolini E, Lo Surdo P, Maruggi G, Spraggon G, Bottomley MJ, Malito E. Structures of NHBA elucidate a broadly conserved epitope identified by a vaccine induced antibody. PLoS One 2018; 13:e0201922. [PMID: 30133484 PMCID: PMC6104945 DOI: 10.1371/journal.pone.0201922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Accepted: 06/28/2018] [Indexed: 11/18/2022] Open
Abstract
Neisserial heparin binding antigen (NHBA) is one of three main recombinant protein antigens in 4CMenB, a vaccine for the prevention of invasive meningococcal disease caused by Neisseria meningitidis serogroup B. NHBA is a surface-exposed lipoprotein composed of a predicted disordered N-terminal region, an arginine-rich region that binds heparin, and a C-terminal domain that folds as an anti-parallel β-barrel and that upon release after cleavage by human proteases alters endothelial permeability. NHBA induces bactericidal antibodies in humans, and NHBA-specific antibodies elicited by the 4CMenB vaccine contribute to serum bactericidal activity, the correlate of protection. To better understand the structural bases of the human antibody response to 4CMenB vaccination and to inform antigen design, we used X-ray crystallography to elucidate the structures of two C-terminal fragments of NHBA, either alone or in complex with the Fab derived from the vaccine-elicited human monoclonal antibody 5H2, and the structure of the unbound Fab 5H2. The structures reveal details on the interaction between an N-terminal β-hairpin fragment and the β-barrel, and explain how NHBA is capable of generating cross-reactive antibodies through an extensive conserved conformational epitope that covers the entire C-terminal face of the β-barrel. By providing new structural information on a vaccine antigen and on the human immune response to vaccination, these results deepen our molecular understanding of 4CMenB, and might also aid future vaccine design projects.
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Affiliation(s)
| | | | | | | | | | | | | | - Glen Spraggon
- Genomics Institute of the Novartis Research Foundation, San Diego, CA, United States of America
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40
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Mohite GM, Kumar R, Panigrahi R, Navalkar A, Singh N, Datta D, Mehra S, Ray S, Gadhe LG, Das S, Singh N, Chatterjee D, Kumar A, Maji SK. Comparison of Kinetics, Toxicity, Oligomer Formation, and Membrane Binding Capacity of α-Synuclein Familial Mutations at the A53 Site, Including the Newly Discovered A53V Mutation. Biochemistry 2018; 57:5183-5187. [PMID: 29771508 DOI: 10.1021/acs.biochem.8b00314] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The involvement of α-synuclein (α-Syn) amyloid formation in Parkinson's disease (PD) pathogenesis is supported by the discovery of α-Syn gene (SNCA) mutations linked with familial PD, which are known to modulate the oligomerization and aggregation of α-Syn. Recently, the A53V mutation has been discovered, which leads to late-onset PD. In this study, we characterized for the first time the biophysical properties of A53V, including the aggregation propensities, toxicity of aggregated species, and membrane binding capability, along with those of all familial mutations at the A53 position. Our data suggest that the A53V mutation accelerates fibrillation of α-Syn without affecting the overall morphology or cytotoxicity of fibrils compared to those of the wild-type (WT) protein. The aggregation propensity for A53 mutants is found to decrease in the following order: A53T > A53V > WT > A53E. In addition, a time course aggregation study reveals that the A53V mutant promotes early oligomerization similar to the case for the A53T mutation. It promotes the largest amount of oligomer formation immediately after dissolution, which is cytotoxic. Although in the presence of membrane-mimicking environments, the A53V mutation showed an extent of helix induction capacity similar to that of the WT protein, it exhibited less binding to lipid vesicles. The nuclear magnetic resonance study revealed unique chemical shift perturbations caused by the A53V mutation compared to those caused by other mutations at the A53 site. This study might help to establish the disease-causing mechanism of A53V in PD pathology.
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Affiliation(s)
- Ganesh M Mohite
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Rakesh Kumar
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Rajlaxmi Panigrahi
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Ambuja Navalkar
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Nitu Singh
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Debalina Datta
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Surabhi Mehra
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Soumik Ray
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Laxmikant G Gadhe
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Subhadeep Das
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Namrata Singh
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Debdeep Chatterjee
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
| | - Samir K Maji
- Department of Biosciences and Bioengineering , IIT Bombay , Powai, Mumbai , India 400076
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41
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Mozhdehi D, Luginbuhl KM, Simon JR, Dzuricky M, Berger R, Varol HS, Huang FC, Buehne KL, Mayne NR, Weitzhandler I, Bonn M, Parekh SH, Chilkoti A. Genetically encoded lipid-polypeptide hybrid biomaterials that exhibit temperature-triggered hierarchical self-assembly. Nat Chem 2018; 10:496-505. [PMID: 29556049 PMCID: PMC6676901 DOI: 10.1038/s41557-018-0005-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Accepted: 01/11/2018] [Indexed: 11/09/2022]
Abstract
Post-translational modification of proteins is a strategy widely used in biological systems. It expands the diversity of the proteome and allows for tailoring of both the function and localization of proteins within cells as well as the material properties of structural proteins and matrices. Despite their ubiquity in biology, with a few exceptions, the potential of post-translational modifications in biomaterials synthesis has remained largely untapped. As a proof of concept to demonstrate the feasibility of creating a genetically encoded biohybrid material through post-translational modification, we report here the generation of a family of three stimulus-responsive hybrid materials-fatty-acid-modified elastin-like polypeptides-using a one-pot recombinant expression and post-translational lipidation methodology. These hybrid biomaterials contain an amphiphilic domain, composed of a β-sheet-forming peptide that is post-translationally functionalized with a C14 alkyl chain, fused to a thermally responsive elastin-like polypeptide. They exhibit temperature-triggered hierarchical self-assembly across multiple length scales with varied structure and material properties that can be controlled at the sequence level.
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Affiliation(s)
- Davoud Mozhdehi
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Kelli M Luginbuhl
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Joseph R Simon
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Michael Dzuricky
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Rüdiger Berger
- Physics at Interfaces, Max Planck Institute for Polymer Research, Mainz, Germany
| | - H Samet Varol
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany
| | - Fred C Huang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Kristen L Buehne
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Nicholas R Mayne
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Isaac Weitzhandler
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Mischa Bonn
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany
| | - Sapun H Parekh
- Department of Molecular Spectroscopy, Max Planck Institute for Polymer Research, Mainz, Germany
| | - Ashutosh Chilkoti
- NSF Research Triangle Materials Research Science and Engineering Center, Department of Biomedical Engineering, Duke University, Durham, NC, USA.
- Department of Biomedical Engineering, Duke University, Durham, NC, USA.
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42
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Wang CY, Chang PM, Ary ML, Allen BD, Chica RA, Mayo SL, Olafson BD. ProtaBank: A repository for protein design and engineering data. Protein Sci 2018; 27:1113-1124. [PMID: 29575358 PMCID: PMC5980626 DOI: 10.1002/pro.3406] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/13/2018] [Accepted: 03/21/2018] [Indexed: 01/01/2023]
Abstract
We present ProtaBank, a repository for storing, querying, analyzing, and sharing protein design and engineering data in an actively maintained and updated database. ProtaBank provides a format to describe and compare all types of protein mutational data, spanning a wide range of properties and techniques. It features a user‐friendly web interface and programming layer that streamlines data deposition and allows for batch input and queries. The database schema design incorporates a standard format for reporting protein sequences and experimental data that facilitates comparison of results across different data sets. A suite of analysis and visualization tools are provided to facilitate discovery, to guide future designs, and to benchmark and train new predictive tools and algorithms. ProtaBank will provide a valuable resource to the protein engineering community by storing and safeguarding newly generated data, allowing for fast searching and identification of relevant data from the existing literature, and exploring correlations between disparate data sets. ProtaBank invites researchers to contribute data to the database to make it accessible for search and analysis. ProtaBank is available at https://protabank.org.
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Affiliation(s)
- Connie Y Wang
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106
| | - Paul M Chang
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106
| | - Marie L Ary
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106
| | - Benjamin D Allen
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106.,Department of Biochemistry and Molecular Biology, and the Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, 16802
| | - Roberto A Chica
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada
| | - Stephen L Mayo
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106.,Division of Biology and Biological Engineering, and Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125
| | - Barry D Olafson
- Protabit LLC, 129 N. Hill Avenue, Suite 102, Pasadena, California, 91106
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43
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Marafon G, Motta MA, Toniolo C, Moretto A. F
rom self‐assembled peptide‐ynes to peptide polyacetylenes and polydiacetylenes. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Giulia Marafon
- Department of Chemical SciencesUniversity of PadovaPadova35131 Italy
| | | | - Claudio Toniolo
- Department of Chemical SciencesUniversity of PadovaPadova35131 Italy
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44
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Ohgo K, Dabalos CL, Kumashiro KK. Solid-State NMR Spectroscopy and Isotopic Labeling Target Abundant Dipeptide Sequences in Elastin’s Hydrophobic Domains. Macromolecules 2018. [DOI: 10.1021/acs.macromol.7b02616] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kosuke Ohgo
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Chester L. Dabalos
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
| | - Kristin K. Kumashiro
- Department of Chemistry, University of Hawaii, 2545 McCarthy Mall, Honolulu, Hawaii 96822, United States
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45
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Cieplak AS. Protein folding, misfolding and aggregation: The importance of two-electron stabilizing interactions. PLoS One 2017; 12:e0180905. [PMID: 28922400 PMCID: PMC5603215 DOI: 10.1371/journal.pone.0180905] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 06/22/2017] [Indexed: 12/17/2022] Open
Abstract
Proteins associated with neurodegenerative diseases are highly pleiomorphic and may adopt an all-α-helical fold in one environment, assemble into all-β-sheet or collapse into a coil in another, and rapidly polymerize in yet another one via divergent aggregation pathways that yield broad diversity of aggregates’ morphology. A thorough understanding of this behaviour may be necessary to develop a treatment for Alzheimer’s and related disorders. Unfortunately, our present comprehension of folding and misfolding is limited for want of a physicochemical theory of protein secondary and tertiary structure. Here we demonstrate that electronic configuration and hyperconjugation of the peptide amide bonds ought to be taken into account to advance such a theory. To capture the effect of polarization of peptide linkages on conformational and H-bonding propensity of the polypeptide backbone, we introduce a function of shielding tensors of the Cα atoms. Carrying no information about side chain-side chain interactions, this function nonetheless identifies basic features of the secondary and tertiary structure, establishes sequence correlates of the metamorphic and pH-driven equilibria, relates binding affinities and folding rate constants to secondary structure preferences, and manifests common patterns of backbone density distribution in amyloidogenic regions of Alzheimer’s amyloid β and tau, Parkinson’s α-synuclein and prions. Based on those findings, a split-intein like mechanism of molecular recognition is proposed to underlie dimerization of Aβ, tau, αS and PrPC, and divergent pathways for subsequent association of dimers are outlined; a related mechanism is proposed to underlie formation of PrPSc fibrils. The model does account for: (i) structural features of paranuclei, off-pathway oligomers, non-fibrillar aggregates and fibrils; (ii) effects of incubation conditions, point mutations, isoform lengths, small-molecule assembly modulators and chirality of solid-liquid interface on the rate and morphology of aggregation; (iii) fibril-surface catalysis of secondary nucleation; and (iv) self-propagation of infectious strains of mammalian prions.
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Affiliation(s)
- Andrzej Stanisław Cieplak
- Department of Chemistry, Bilkent University, Ankara, Turkey
- Department of Chemistry, Yale University, New Haven, Connecticut, United States of America
- Department of Chemistry, Brandeis University, Waltham, Massachusetts, United States of America
- * E-mail:
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46
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Cohen RD, Pielak GJ. Quinary interactions with an unfolded state ensemble. Protein Sci 2017; 26:1698-1703. [PMID: 28571108 PMCID: PMC5563149 DOI: 10.1002/pro.3206] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 05/21/2017] [Accepted: 05/26/2017] [Indexed: 01/10/2023]
Abstract
Anfinsen's thermodynamic hypothesis states that the native three-dimensional fold of a protein represents the structure with the lowest Gibbs free energy. Changes in the free energy of denaturation can arise from changes to the folded state, the unfolded state, or both. It has been recently recognized that quinary interactions, transient contacts that take place only in cells, can modulate protein stability through interactions involving the folded state. Here we show that the cellular environment can also remodel the unfolded state ensemble.
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Affiliation(s)
- Rachel D. Cohen
- Department of ChemistryUniversity of North CarolinaChapel HillNorth Carolina27599
| | - Gary J. Pielak
- Department of ChemistryUniversity of North CarolinaChapel HillNorth Carolina27599
- Department of Biochemistry and BiophysicsUniversity of North CarolinaChapel HillNorth Carolina27599
- Lineberger Comprehensive Cancer Center, University of North CarolinaChapel HillNorth Carolina27599
- Integrative Program for Biological and Genome SciencesUniversity of North CarolinaChapel HillNorth Carolina27599
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47
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Abstract
The effects of small (∼102 Da) and larger (>103 Da) cosolutes on the equilibrium stability of monomeric globular proteins are broadly understood, excluding volume stabilizes proteins and chemical interactions are stabilizing when repulsive, but destabilizing when attractive. Proteins, however, rarely work alone. Here, we investigate the effects of small and large cosolutes on the equilibrium stability of the simplest defined protein-protein interactions, the side-by-side homodimer formed by the A34F variant of the 56-residue B1 domain of protein G. We used 19F nuclear magnetic resonance spectroscopy to quantify the effects of urea, trimethylamine oxide, Ficoll, and more physiologically relevant cosolutes on the dimer dissociation constant. The data reveal the same stabilizing and destabilizing influences from chemical interactions as observed in studies of protein stability. Results with more physiologically relevant molecules such as bovine serum albumin, lysozyme, and reconstituted Escherichia coli cytosol reflect the importance of chemical interactions between these cosolutes and the test protein. Our study serves as a stepping-stone to a more complete understanding of crowding effects on protein-protein interactions.
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Affiliation(s)
- Alex J. Guseman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gary J. Pielak
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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48
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Effect of peptide self-assembly on the rheological properties of alginate-peptide conjugates solutions. POLYMER 2017. [DOI: 10.1016/j.polymer.2016.11.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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49
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Malik AA, Veltri M, Boddington KF, Singh KK, Graether SP. Genome Analysis of Conserved Dehydrin Motifs in Vascular Plants. FRONTIERS IN PLANT SCIENCE 2017; 8:709. [PMID: 28523013 PMCID: PMC5415607 DOI: 10.3389/fpls.2017.00709] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 04/18/2017] [Indexed: 05/02/2023]
Abstract
Dehydrins, a large family of abiotic stress proteins, are defined by the presence of a mostly conserved motif known as the K-segment, and may also contain two other conserved motifs known as the Y-segment and S-segment. Using the dehydrin literature, we developed a sequence motif definition of the K-segment, which we used to create a large dataset of dehydrin sequences by searching the Pfam00257 dehydrin dataset and the Phytozome 10 sequences of vascular plants. A comprehensive analysis of these sequences reveals that lysine residues are highly conserved in the K-segment, while the amino acid type is often conserved at other positions. Despite the Y-segment name, the central tyrosine is somewhat conserved, but can be substituted with two other small aromatic amino acids (phenylalanine or histidine). The S-segment contains a series of serine residues, but in some proteins is also preceded by a conserved LHR sequence. In many dehydrins containing all three of these motifs the S-segment is linked to the K-segment by a GXGGRRKK motif (where X can be any amino acid), suggesting a functional linkage between these two motifs. An analysis of the sequences shows that the dehydrin architecture and several biochemical properties (isoelectric point, molecular mass, and hydrophobicity score) are dependent on each other, and that some dehydrin architectures are overexpressed during certain abiotic stress, suggesting that they may be optimized for a specific abiotic stress while others are involved in all forms of dehydration stress (drought, cold, and salinity).
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50
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Hiew SH, Guerette PA, Zvarec OJ, Phillips M, Zhou F, Su H, Pervushin K, Orner BP, Miserez A. Modular peptides from the thermoplastic squid sucker ring teeth form amyloid-like cross-β supramolecular networks. Acta Biomater 2016; 46:41-54. [PMID: 27693688 DOI: 10.1016/j.actbio.2016.09.040] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 09/23/2016] [Accepted: 09/28/2016] [Indexed: 12/22/2022]
Abstract
The hard sucker ring teeth (SRT) from decapodiforme cephalopods, which are located inside the sucker cups lining the arms and tentacles of these species, have recently emerged as a unique model structure for biomimetic structural biopolymers. SRT are entirely composed of modular, block co-polymer-like proteins that self-assemble into a large supramolecular network. In order to unveil the molecular principles behind SRT's self-assembly and robustness, we describe a combinatorial screening assay that maps the molecular-scale interactions between the most abundant modular peptide blocks of suckerin proteins. By selecting prominent interaction hotspots from this assay, we identified four peptides that exhibited the strongest homo-peptidic interactions, and conducted further in-depth biophysical characterizations complemented by molecular dynamic (MD) simulations to investigate the nature of these interactions. Circular Dichroism (CD) revealed conformations that transitioned from semi-extended poly-proline II (PII) towards β-sheet structure. The peptides spontaneously self-assembled into microfibers enriched with cross β-structures, as evidenced by Fourier-Transform Infrared Spectroscopy (FTIR) and Congo red staining. Nuclear Magnetic Resonance (NMR) experiments identified the residues involved in the hydrogen-bonded network and demonstrated that these self-assembled β-sheet-based fibers exhibit high protection factors that bear resemblance to amyloids. The high stability of the β-sheet network and an amyloid-like model of fibril assembly were supported by MD simulations. The work sheds light on how Nature has evolved modular sequence design for the self-assembly of mechanically robust functional materials, and expands our biomolecular toolkit to prepare load-bearing biomaterials from protein-based block co-polymers and self-assembled peptides. STATEMENT OF SIGNIFICANCE The sucker ring teeth (SRT) located on the arms and tentacles of cephalopods represent as a very promising protein-based biopolymer with the potential to rival silk in biomedical and engineering applications. SRT are made of modular, block co-polymer like proteins (suckerins), which assemble into a semicrystalline polymer reinforced by nano-confined β-sheets, resulting in a supramolecular network with mechanical properties that match those of the strongest engineering polymers. In this study, we aimed to understand the molecular mechanisms behind SRT's self-assembly and robustness. The most abundant modular peptidic blocks of suckerin proteins were studied by various spectroscopic methods, which demonstrate that SRT peptides form amyloid-like cross-β structures.
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