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Maltseva D, Gudbrandsdottir R, Kizilsavas G, Horinek D, Gonella G. Location and Conformation of the LKα14 Peptide in Water/Ethanol Mixtures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:469-477. [PMID: 33356282 PMCID: PMC7871320 DOI: 10.1021/acs.langmuir.0c03132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 12/14/2020] [Indexed: 06/12/2023]
Abstract
It is widely recognized that solvation is one of the major factors determining structure and functionality of proteins and long peptides, however it is a formidable challenge to address it both experimentally and computationally. For this reason, simple peptides are used to study fundamental aspects of solvation. It is well established that alcohols can change the peptide conformation and tuning of the alcohol content in solution can dramatically affect folding and, as a consequence, the function of the peptide. In this work, we focus on the leucine and lysine based LKα14 peptide designed to adopt an α-helical conformation at an apolar-polar interface. We investigate LKα14 peptide's bulk and interfacial behavior in water/ethanol mixtures combining a suite of experimental techniques (namely, circular dichroism and nuclear magnetic resonance spectroscopy for the bulk solution, surface pressure measurements and vibrational sum frequency generation spectroscopy for the air-solution interface) with molecular dynamics simulations. We observe that ethanol highly affects both the peptide location and conformation. At low ethanol content LKα14 lacks a clear secondary structure in bulk and shows a clear preference to reside at the air-solution interface. When the ethanol content in solution increases, the peptide's interfacial affinity is markedly reduced and the peptide approaches a stable α-helical conformation in bulk facilitated by the amphiphilic nature of the ethanol molecules.
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Affiliation(s)
- Daria Maltseva
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | | | - Gönül Kizilsavas
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Dominik Horinek
- Institute
for Physical and Theoretical Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Grazia Gonella
- Max
Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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2
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Shaw WJ, Tarasevich BJ, Buchko GW, Arachchige RMJ, Burton SD. Controls of nature: Secondary, tertiary, and quaternary structure of the enamel protein amelogenin in solution and on hydroxyapatite. J Struct Biol 2020; 212:107630. [PMID: 32979496 PMCID: PMC7744360 DOI: 10.1016/j.jsb.2020.107630] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/12/2020] [Accepted: 09/17/2020] [Indexed: 10/23/2022]
Abstract
Amelogenin, a protein critical to enamel formation, is presented as a model for understanding how the structure of biomineralization proteins orchestrate biomineral formation. Amelogenin is the predominant biomineralization protein in the early stages of enamel formation and contributes to the controlled formation of hydroxyapatite (HAP) enamel crystals. The resulting enamel mineral is one of the hardest tissues in the human body and one of the hardest biominerals in nature. Structural studies have been hindered by the lack of techniques to evaluate surface adsorbed proteins and by amelogenin's disposition to self-assemble. Recent advancements in solution and solid state nuclear magnetic resonance (NMR) spectroscopy, atomic force microscopy (AFM), and recombinant isotope labeling strategies are now enabling detailed structural studies. These recent studies, coupled with insights from techniques such as CD and IR spectroscopy and computational methodologies, are contributing to important advancements in our structural understanding of amelogenesis. In this review we focus on recent advances in solution and solid state NMR spectroscopy and in situ AFM that reveal new insights into the secondary, tertiary, and quaternary structure of amelogenin by itself and in contact with HAP. These studies have increased our understanding of the interface between amelogenin and HAP and how amelogenin controls enamel formation.
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Affiliation(s)
- Wendy J Shaw
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA.
| | - Barbara J Tarasevich
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Garry W Buchko
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA; School of Molecular Bioscience, Washington State University, Pullman, WA 99164, USA
| | - Rajith M J Arachchige
- Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Sarah D Burton
- Earth and Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99352, USA
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3
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Ozgur B, Sayar M. Representation of the conformational ensemble of peptides in coarse grained simulations. J Chem Phys 2020; 153:054108. [DOI: 10.1063/5.0012391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Mehmet Sayar
- Chemical and Biological Engineering and Mechanical Engineering Departments, College of Engineering, Koç University, 34450 Istanbul, Turkey
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4
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Emani PS, Yimer YY, Davidowski SK, Gebhart RN, Ferreira HE, Kuprov I, Pfaendtner J, Drobny GP. Combining Molecular and Spin Dynamics Simulations with Solid-State NMR: A Case Study of Amphiphilic Lysine-Leucine Repeat Peptide Aggregates. J Phys Chem B 2019; 123:10915-10929. [PMID: 31769684 DOI: 10.1021/acs.jpcb.9b09245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Interpreting dynamics in solid-state molecular systems requires characterization of the potentially heterogeneous environmental contexts of molecules. In particular, the analysis of solid-state nuclear magnetic resonance (ssNMR) data to elucidate molecular dynamics (MD) involves modeling the restriction to overall tumbling by neighbors, as well as the concentrations of water and buffer. In this exploration of the factors that influence motion, we utilize atomistic MD trajectories of peptide aggregates with varying hydration to mimic an amorphous solid-state environment and predict ssNMR relaxation rates. We also account for spin diffusion in multiply spin-labeled (up to 19 nuclei) residues, with several models of dipolar-coupling networks. The framework serves as a general approach to determine essential spin couplings affecting relaxation, benchmark MD force fields, and reveal the hydration dependence of dynamics in a crowded environment. We demonstrate the methodology on a previously characterized amphiphilic 14-residue lysine-leucine repeat peptide, LKα14 (Ac-LKKLLKLLKKLLKL-c), which has an α-helical secondary structure and putatively forms leucine-burying tetramers in the solid state. We measure the R1 relaxation rates of uniformly 13C-labeled and site-specific 2H-labeled leucines in the hydrophobic core of LKα14 at multiple hydration levels. Studies of 9 and 18 tetramer bundles reveal the following: (a) for the incoherent component of 13C relaxation, the nearest-neighbor spin interactions dominate, while the 1H-1H interactions have minimal impact; (b) the AMBER ff14SB dihedral barriers for the leucine Cγ-Cδ bond ("methyl rotation barriers") must be lowered by a factor of 0.7 to better match the 2H data; (c) proton-driven spin diffusion explains some of the discrepancy between experimental and simulated rates for the Cβ and Cα nuclei; and (d) 13C relaxation rates are mostly underestimated in the MD simulations at all hydrations, and the discrepancies identify likely motions missing in the 50 ns MD trajectories.
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Affiliation(s)
- Prashant S Emani
- Department of Chemistry , University of Washington , Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Yeneneh Y Yimer
- Department of Chemical Engineering , University of Washington , 105 Benson Hall, Box 351750 , Seattle , Washington 98195-1750 , United States
| | - Stephen K Davidowski
- Department of Chemistry , University of Washington , Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Rachel N Gebhart
- Department of Chemistry , University of Washington , Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Helen E Ferreira
- Department of Chemistry , University of Washington , Box 351700 , Seattle , Washington 98195-1700 , United States
| | - Ilya Kuprov
- Department of Chemistry , University of Southampton , Highfield, Southampton SO17 1BJ , U.K
| | - Jim Pfaendtner
- Department of Chemical Engineering , University of Washington , 105 Benson Hall, Box 351750 , Seattle , Washington 98195-1750 , United States
| | - Gary P Drobny
- Department of Chemistry , University of Washington , Box 351700 , Seattle , Washington 98195-1700 , United States
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5
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Zerfaß C, Buchko GW, Shaw WJ, Hobe S, Paulsen H. Secondary structure and dynamics study of the intrinsically disordered silica-mineralizing peptide P 5 S 3 during silicic acid condensation and silica decondensation. Proteins 2017; 85:2111-2126. [PMID: 28799215 PMCID: PMC5760248 DOI: 10.1002/prot.25366] [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: 05/29/2017] [Revised: 08/07/2017] [Accepted: 08/08/2017] [Indexed: 11/08/2022]
Abstract
The silica forming repeat R5 of sil1 from Cylindrotheca fusiformis was the blueprint for the design of P5 S3 , a 50-residue peptide which can be produced in large amounts by recombinant bacterial expression. It contains 5 protein kinase A target sites and is highly cationic due to 10 lysine and 10 arginine residues. In the presence of supersaturated orthosilicic acid P5 S3 enhances silica-formation whereas it retards the dissolution of amorphous silica (SiO2 ) at globally undersaturated concentrations. The secondary structure of P5 S3 during these 2 processes was studied by circular dichroism (CD) spectroscopy, complemented by nuclear magnetic resonance (NMR) spectroscopy of the peptide in the absence of silicate. The NMR studies of dual-labeled (13 C, 15 N) P5 S3 revealed a disordered structure at pH 2.8 and 4.5. Within the pH range of 4.5-9.5 in the absence of silicic acid, the CD data showed a disordered structure with the suggestion of some polyproline II character. Upon silicic acid polymerization and during dissolution of preformed silica, the CD spectrum of P5 S3 indicated partial transition into an α-helical conformation which was transient during silica-dissolution. The secondary structural changes observed for P5 S3 correlate with the presence of oligomeric/polymeric silicic acid, presumably due to P5 S3 -silica interactions. These P5 S3 -silica interactions appear, at least in part, ionic in nature since negatively charged dodecylsulfate caused similar perturbations to the P5 S3 CD spectrum as observed with silica, while uncharged ß-d-dodecyl maltoside did not affect the CD spectrum of P5 S3 . Thus, with an associated increase in α-helical character, P5 S3 influences both the condensation of silicic acid into silica and its decondensation back to silicic acid.
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Affiliation(s)
- Christian Zerfaß
- Institute of Molecular Physiology, Johannes Gutenberg University, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
- Graduate School Materials Science in Mainz, Staudinger Weg 9, 55128 Mainz, Germany
| | - Garry W. Buchko
- Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Wendy J. Shaw
- Pacific Northwest National Laboratory, Richland, WA 99354, United States
| | - Stephan Hobe
- Institute of Molecular Physiology, Johannes Gutenberg University, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
| | - Harald Paulsen
- Institute of Molecular Physiology, Johannes Gutenberg University, Johannes-von-Müller-Weg 6, 55128 Mainz, Germany
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6
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Barkley DA, Rokhlenko Y, Marine JE, David R, Sahoo D, Watson MD, Koga T, Osuji CO, Rudick JG. Hexagonally Ordered Arrays of α-Helical Bundles Formed from Peptide-Dendron Hybrids. J Am Chem Soc 2017; 139:15977-15983. [PMID: 29043793 DOI: 10.1021/jacs.7b09737] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Combining monodisperse building blocks that have distinct folding properties serves as a modular strategy for controlling structural complexity in hierarchically organized materials. We combine an α-helical bundle-forming peptide with self-assembling dendrons to better control the arrangement of functional groups within cylindrical nanostructures. Site-specific grafting of dendrons to amino acid residues on the exterior of the α-helical bundle yields monodisperse macromolecules with programmable folding and self-assembly properties. The resulting hybrid biomaterials form thermotropic columnar hexagonal mesophases in which the peptides adopt an α-helical conformation. Bundling of the α-helical peptides accompanies self-assembly of the peptide-dendron hybrids into cylindrical nanostructures. The bundle stoichiometry in the mesophase agrees well with the size found in solution for α-helical bundles of peptides with a similar amino acid sequence.
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Affiliation(s)
- Deborah A Barkley
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Yekaterina Rokhlenko
- Department of Chemical and Environmental Engineering, Yale University , New Haven, Connecticut 06511, United States
| | - Jeannette E Marine
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Rachelle David
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Dipankar Sahoo
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Matthew D Watson
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
| | - Tadanori Koga
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States.,Department of Materials Science and Engineering, Stony Brook University , Stony Brook, New York 11794, United States
| | - Chinedum O Osuji
- Department of Chemical and Environmental Engineering, Yale University , New Haven, Connecticut 06511, United States
| | - Jonathan G Rudick
- Department of Chemistry, Stony Brook University , Stony Brook, New York 11794, United States
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7
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Marine JE, Song S, Liang X, Rudick JG. Synthesis and Self-Assembly of Bundle-Forming α-Helical Peptide-Dendron Hybrids. Biomacromolecules 2016; 17:336-44. [PMID: 26674475 PMCID: PMC4710556 DOI: 10.1021/acs.biomac.5b01452] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Dendronized helix bundle assemblies combine the sequence diversity and folding properties of proteins with the tailored physical properties of dendrimers. Assembly of peptide-dendron hybrids into α-helical bundles encapsulates the helix bundle motif in a dendritic sheath that will allow the functional, protein-like domain to be transplanted to nonbiological environments. A bioorthogonal graft-to synthetic strategy for preparing helix bundle-forming peptide-dendron hybrids is described herein for hybrids 1a, 1b, and 2. Titration experiments monitored by circular dichroism spectroscopy support our self-assembly model for how the peptide-dendron hybrids self-assemble into α-helical bundles with the dendrons on outside of the bundle.
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Affiliation(s)
- Jeannette E. Marine
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Shuang Song
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Xiaoli Liang
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
| | - Jonathan G. Rudick
- Department of Chemistry, Stony Brook University, Stony Brook, New York 11794-3400, United States
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8
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Zane AC, Michelet C, Roehrich A, Emani PS, Drobny GP. Silica morphogenesis by lysine-leucine peptides with hydrophobic periodicity. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2014; 30:7152-7161. [PMID: 24896500 DOI: 10.1021/la501444t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The use of biomimetic approaches in the production of inorganic nanostructures is of great interest to the scientific and industrial community due to the relatively moderate physical conditions needed. In this vein, taking cues from silaffin proteins used by unicellular diatoms, several studies have identified peptide candidates for the production of silica nanostructures. In the current article, we study intensively one such silica-precipitating peptide, LKα14 (Ac-LKKLLKLLKKLLKL-c), an amphiphilic lysine/leucine repeat peptide that self-organizes into an α-helical secondary structure under appropriate concentration and buffer conditions. The suggested mechanism of precipitation is that the sequestration of hydrophilic lysines on one side of this helix allows interaction with the negatively charged surface of silica nanoparticles, which in turn can aggregate further into larger structures. To investigate the process, we carry out 1D and 2D solid-state NMR (ssNMR) studies on samples with one or two uniformly (13)C- and (15)N-labeled residues to determine the backbone and side-chain chemical shifts. We also further study the dynamics of two leucine residues in the sequence through (13)C spin-lattice relaxation times (T1) to determine the impact of silica coprecipitation on their mobility. Our results confirm the α-helical secondary structure in both the neat and silica-complexed states of the peptide, and the patterns of chemical shift and relaxation time changes between the two states suggest possible mechanisms of self-aggregation and silica precipitation.
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Affiliation(s)
- Ariel C Zane
- Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195, United States
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9
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Structural characterization of a β-hydroxyacid dehydrogenase from Geobacter sulfurreducens and Geobacter metallireducens with succinic semialdehyde reductase activity. Biochimie 2014; 104:61-9. [PMID: 24878278 DOI: 10.1016/j.biochi.2014.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 05/09/2014] [Indexed: 11/23/2022]
Abstract
Beta-hydroxyacid dehydrogenase (β-HAD) genes have been identified in all sequenced genomes of eukaryotes and prokaryotes. Their gene products catalyze the NAD(+)- or NADP(+)-dependent oxidation of various β-hydroxy acid substrates into their corresponding semialdehyde. In many fungal and bacterial genomes, multiple β-HAD genes are observed leading to the hypothesis that these gene products may have unique, uncharacterized metabolic roles specific to their species. The genomes of Geobacter sulfurreducens and Geobacter metallireducens each contain two potential β-HAD genes. The protein sequences of one pair of these genes, Gs-βHAD (Q74DE4) and Gm-βHAD (Q39R98), have 65% sequence identity and 77% sequence similarity with each other. Both proteins are observed to reduce succinic semialdehyde, a 4-carbon substrate instead of the typical β-HAD 3-carbon substrate, to γ-hydroxybutyric acid. To further explore the structural and functional characteristics of these two β-HADs with a less frequently observed substrate specificity, crystal structures for Gs-βHAD and Gm-βHAD in complex with NADP(+) were determined to a resolution of 1.89 Å and 2.07 Å, respectively. The structures of both proteins are similar, composed of 14 α-helices and nine β-strands organized into two domains. Domain 1 (1-165) adopts a typical Rossmann fold composed of two α/β units: a six-strand parallel β-sheet surrounded by six α-helices (α1-α6) followed by a mixed three-strand β-sheet surrounded by two α-helices (α7 and α8). Domain 2 (166-287) is composed of a bundle of seven α-helices (α9-α14). Four functional regions conserved in all β-HADs are spatially located near each other, with a buried molecule of NADP(+), at the interdomain cleft. Comparison of these Geobacter structures to a closely related β-HAD from Arabidopsis thaliana in the apo-NADP(+) and apo-substrate bound state suggests that NADP(+) binding effects a rigid body rotation between Domains 1 and 2. Bound near the Substrate-Binding and Catalysis Regions in two of the eight protomers in the asymmetric unit of Gm-βHAD is a glycerol molecule that may mimic features of bound biological substrates.
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10
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Gerig JT. Toward a Molecular Dynamics Force Field for Simulations of 40% Trifluoroethanol–Water. J Phys Chem B 2014; 118:1471-80. [DOI: 10.1021/jp408879g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- J. T. Gerig
- Department of Chemistry and
Biochemistry, University of California, Santa Barbara, Santa Barbara, California 93106, United States
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