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Singh Y, Cudic P, Cudic M. Front Cover: Exploring Glycan Binding Specificity of Odorranalectin by Alanine Scanning Library (Eur. J. Org. Chem. 28/2022). European J Org Chem 2022. [DOI: 10.1002/ejoc.202200835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
| | - Predrag Cudic
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
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Singh Y, Cudic P, Cudic M. Exploring Glycan Binding Specificity of Odorranalectin by Alanine Scanning Library. European J Org Chem 2022; 2022. [PMID: 36120398 PMCID: PMC9479679 DOI: 10.1002/ejoc.202200302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Fluorescently labelled alanine scan analogues of odorranalectin (OL), a cyclic peptide that exhibits lectin like properties, were screened for binding BSA-conjugated monosaccharides using an enzyme-linked lectin assay (ELLA). Results revealed that Lys5, Phe7, Tyr9, Gly12, Leu14, and Thr17 were crucial for binding BSA-L-fucose, BSA-D-galactose and BSA-N-acetyl-D-galactosamine. Notably, Ala substitution of Ser3, Pro4, and Val13 resulted in higher binding affinities compared to the native OL. The obtained data also indicated that Arg8 plays an important role in differentiation of binding for BSA-L-fucose/D-galactose from BSA-N-acetyl-D-galactosamine. The thermodynamics of binding of the selected alanine analogues was evaluated by isothermal titration calorimetry. Low to moderate binding affinities were determined for the tetravalent MUC1 glycopeptide and asialofetuin, respectively, and high for the fucose rich polysaccharide, fucoidan. The thermodynamic profile of interactions with asialofetuin exhibits shift to an entropy-driven mechanism compared to the fucoidan, which displayed an enthalpyentropy compensation, typically associated with the carbohydratelectin recognition process.
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Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
| | - Predrag Cudic
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry Florida Atlantic University 777 Glades Road Boca Raton Florida 33431 United States
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Singh Y, Regmi D, Ormaza D, Ayyalasomayajula R, Vela N, Mundim G, Du D, Minond D, Cudic M. Mucin-Type O-Glycosylation Proximal to β-Secretase Cleavage Site Affects APP Processing and Aggregation Fate. Front Chem 2022; 10:859822. [PMID: 35464218 PMCID: PMC9023740 DOI: 10.3389/fchem.2022.859822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/07/2022] [Indexed: 12/04/2022] Open
Abstract
The amyloid-β precursor protein (APP) undergoes proteolysis by β- and γ-secretases to form amyloid-β peptides (Aβ), which is a hallmark of Alzheimer’s disease (AD). Recent findings suggest a possible role of O-glycosylation on APP’s proteolytic processing and subsequent fate for AD-related pathology. We have previously reported that Tyr681-O-glycosylation and the Swedish mutation accelerate cleavage of APP model glycopeptides by β-secretase (amyloidogenic pathway) more than α-secretase (non-amyloidogenic pathway). Therefore, to further our studies, we have synthesized additional native and Swedish-mutated (glyco)peptides with O-GalNAc moiety on Thr663 and/or Ser667 to explore the role of glycosylation on conformation, secretase activity, and aggregation kinetics of Aβ40. Our results show that conformation is strongly dependent on external conditions such as buffer ions and solvent polarity as well as internal modifications of (glyco)peptides such as length, O-glycosylation, and Swedish mutation. Furthermore, the level of β-secretase activity significantly increases for the glycopeptides containing the Swedish mutation compared to their nonglycosylated and native counterparts. Lastly, the glycopeptides impact the kinetics of Aβ40 aggregation by significantly increasing the lag phase and delaying aggregation onset, however, this effect is less pronounced for its Swedish-mutated counterparts. In conclusion, our results confirm that the Swedish mutation and/or O-glycosylation can render APP model glycopeptides more susceptible to cleavage by β-secretase. In addition, this study sheds new light on the possible role of glycosylation and/or glycan density on the rate of Aβ40 aggregation.
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Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deepika Regmi
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - David Ormaza
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Ramya Ayyalasomayajula
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Nancy Vela
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Gustavo Mundim
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deguo Du
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Dmitriy Minond
- College of Pharmacy and Rumbaugh-Goodwin Institute for Cancer Research, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
- *Correspondence: Maré Cudic,
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Gabius HJ, Cudic M, Diercks T, Kaltner H, Kopitz J, Mayo KH, Murphy PV, Oscarson S, Roy R, Schedlbauer A, Toegel S, Romero A. What is the Sugar Code? Chembiochem 2021; 23:e202100327. [PMID: 34496130 PMCID: PMC8901795 DOI: 10.1002/cbic.202100327] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/07/2021] [Indexed: 12/18/2022]
Abstract
A code is defined by the nature of the symbols, which are used to generate information‐storing combinations (e. g. oligo‐ and polymers). Like nucleic acids and proteins, oligo‐ and polysaccharides are ubiquitous, and they are a biochemical platform for establishing molecular messages. Of note, the letters of the sugar code system (third alphabet of life) excel in coding capacity by making an unsurpassed versatility for isomer (code word) formation possible by variability in anomery and linkage position of the glycosidic bond, ring size and branching. The enzymatic machinery for glycan biosynthesis (writers) realizes this enormous potential for building a large vocabulary. It includes possibilities for dynamic editing/erasing as known from nucleic acids and proteins. Matching the glycome diversity, a large panel of sugar receptors (lectins) has developed based on more than a dozen folds. Lectins ‘read’ the glycan‐encoded information. Hydrogen/coordination bonding and ionic pairing together with stacking and C−H/π‐interactions as well as modes of spatial glycan presentation underlie the selectivity and specificity of glycan‐lectin recognition. Modular design of lectins together with glycan display and the nature of the cognate glycoconjugate account for the large number of post‐binding events. They give an entry to the glycan vocabulary its functional, often context‐dependent meaning(s), hereby building the dictionary of the sugar code.
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Affiliation(s)
- Hans-Joachim Gabius
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida, 33431, USA
| | - Tammo Diercks
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801 A, 48160, Derio, Bizkaia, Spain
| | - Herbert Kaltner
- Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Veterinärstr. 13, 80539, Munich, Germany
| | - Jürgen Kopitz
- Institute of Pathology, Department of Applied Tumor Biology, Faculty of Medicine, Ruprecht-Karls-University Heidelberg, Im Neuenheimer Feld 224, 69120, Heidelberg, Germany
| | - Kevin H Mayo
- Department of Biochemistry, Molecular Biology & Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Paul V Murphy
- CÚRAM - SFI Research Centre for Medical Devices and the, School of Chemistry, National University of Ireland Galway, University Road, Galway, H91 TK33, Ireland
| | - Stefan Oscarson
- Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - René Roy
- Département de Chimie et Biochimie, Université du Québec à Montréal, Case Postale 888, Succ. Centre-Ville Montréal, Québec, H3C 3P8, Canada
| | - Andreas Schedlbauer
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801 A, 48160, Derio, Bizkaia, Spain
| | - Stefan Toegel
- Karl Chiari Lab for Orthopaedic Biology, Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria
| | - Antonio Romero
- Department of Structural and Chemical Biology, CIB Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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Singh Y, Ormaza D, Massetti A, Minond D, Cudic M. Tyrosine O-GalNAc Alters the Conformation and Proteolytic Susceptibility of APP Model Glycopeptides. ACS Chem Neurosci 2021; 12:2974-2980. [PMID: 34324289 PMCID: PMC8378340 DOI: 10.1021/acschemneuro.1c00387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
![]()
The amyloid-β precursor protein (APP) undergoes proteolytic cleavage by α-,
β-, and γ-secretases, to determine its fate in Alzheimer’s disease
(AD) pathogenesis. Recent findings suggest a possible role of
O-glycosylation in APP’s proteolytic processing. Therefore, we
synthesized native and Swedish-double-mutated APP (glyco)peptides with
Tyr681-O-GalNAc. We studied conformational changes and
proteolytic processing using circular dichroism (CD) spectroscopy and enzyme cleavage
assay, respectively. CD analysis was carried out in four solvent systems to evaluate
peptide environment and O-glycosylation induced conformational changes.
The Swedish mutation and Tyr681-O-GalNAc were the key
factors driving conformational changes. Furthermore, the level of α- and
β-secretase activity was increased by the presence of mutation and this effect was
more pronounced for its glycosylated analogues. Our results suggest that
O-glycosylation of Tyr681 can induce a conformational
change in APP and affect its proteolytic processing fate toward the amyloidogenic
pathway.
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Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - David Ormaza
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - Alessandra Massetti
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - Dmitriy Minond
- College of Pharmacy and Rumbaugh-Goodwin Institute for Cancer Research, Nova Southeastern University, 3301 College Ave, Fort Lauderdale, Florida 33314, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E, Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
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Beckwith DM, FitzGerald FG, Rodriguez Benavente MC, Mercer ER, Ludwig AK, Michalak M, Kaltner H, Kopitz J, Gabius HJ, Cudic M. Calorimetric Analysis of the Interplay between Synthetic Tn Antigen-Presenting MUC1 Glycopeptides and Human Macrophage Galactose-Type Lectin. Biochemistry 2021; 60:547-558. [PMID: 33560106 PMCID: PMC8269692 DOI: 10.1021/acs.biochem.0c00942] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/31/2021] [Indexed: 12/25/2022]
Abstract
Human macrophage galactose-type lectin (hMGL, HML, CD301, CLEC10A), a C-type lectin expressed by dendritic cells and macrophages, is a receptor for N-acetylgalactosamine α-linked to serine/threonine residues (Tn antigen, CD175) and its α2,6-sialylated derivative (sTn, CD175s). Because these two epitopes are among malignant cell glycan displays, particularly when presented by mucin-1 (MUC1), assessing the influence of the site and frequency of glycosylation on lectin recognition will identify determinants governing this interplay. Thus, chemical synthesis of the tandem-repeat O-glycan acceptor region of MUC1 and site-specific threonine glycosylation in all permutations were carried out. Isothermal titration calorimetry (ITC) analysis of the binding of hMGL to this library of MUC1 glycopeptides revealed an enthalpy-driven process and an affinity enhancement of an order of magnitude with an increasing glycan count from 6-8 μM for monoglycosylated peptides to 0.6 μM for triglycosylated peptide. ITC measurements performed in D2O permitted further exploration of the solvation dynamics during binding. A shift in enthalpy-entropy compensation and contact position-specific effects with the likely involvement of the peptide surroundings were detected. KinITC analysis revealed a prolonged lifetime of the lectin-glycan complex with increasing glycan valency and with a change in the solvent to D2O.
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Affiliation(s)
- Donella M. Beckwith
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Forrest G. FitzGerald
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Maria C. Rodriguez Benavente
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Elizabeth R. Mercer
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Anna-Kristin Ludwig
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Malwina Michalak
- Department of Applied Tumor Biology, Institute of
Pathology, Medical School of the Ruprecht-Karls-University
Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg,
Germany
| | - Herbert Kaltner
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Jürgen Kopitz
- Department of Applied Tumor Biology, Institute of
Pathology, Medical School of the Ruprecht-Karls-University
Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg,
Germany
| | - Hans-Joachim Gabius
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
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Diercks T, Medrano FJ, FitzGerald FG, Beckwith D, Pedersen MJ, Reihill M, Ludwig AK, Romero A, Oscarson S, Cudic M, Gabius HJ. Galectin-Glycan Interactions: Guidelines for Monitoring by 77 Se NMR Spectroscopy, and Solvent (H 2 O/D 2 O) Impact on Binding. Chemistry 2020; 27:316-325. [PMID: 32955737 PMCID: PMC7839768 DOI: 10.1002/chem.202003143] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/11/2020] [Indexed: 12/19/2022]
Abstract
Functional pairing between cellular glycoconjugates and tissue lectins like galectins has wide (patho)physiological significance. Their study is facilitated by nonhydrolysable derivatives of the natural O‐glycans, such as S‐ and Se‐glycosides. The latter enable extensive analyses by specific 77Se NMR spectroscopy, but still remain underexplored. By using the example of selenodigalactoside (SeDG) and the human galectin‐1 and ‐3, we have evaluated diverse 77Se NMR detection methods and propose selective 1H,77Se heteronuclear Hartmann–Hahn transfer for efficient use in competitive NMR screening against a selenoglycoside spy ligand. By fluorescence anisotropy, circular dichroism, and isothermal titration calorimetry (ITC), we show that the affinity and thermodynamics of SeDG binding by galectins are similar to thiodigalactoside (TDG) and N‐acetyllactosamine (LacNAc), confirming that Se substitution has no major impact. ITC data in D2O versus H2O are similar for TDG and LacNAc binding by both galectins, but a solvent effect, indicating solvent rearrangement at the binding site, is hinted at for SeDG and clearly observed for LacNAc dimers with extended chain length.
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Affiliation(s)
- Tammo Diercks
- NMR Facility, CiC bioGUNE, Parque Tecnológico de Bizkaia, Ed. 800, 48160, Derio, Spain
| | - Francisco J Medrano
- Structural and Chemical Biology, Centro de Investigaciones, Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Forrest G FitzGerald
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Donella Beckwith
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Martin Jaeger Pedersen
- Center for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Mark Reihill
- Center for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Anna-Kristin Ludwig
- Tierärztliche Fakultät, Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, Veterinärstr. 13, 80539, München, Germany
| | - Antonio Romero
- Structural and Chemical Biology, Centro de Investigaciones, Biológicas Margarita Salas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Stefan Oscarson
- Center for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin, 4, Ireland
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Hans-Joachim Gabius
- Tierärztliche Fakultät, Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, Veterinärstr. 13, 80539, München, Germany
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FitzGerald FG, Rodriguez Benavente MC, Garcia C, Rivero Y, Singh Y, Wang H, Fields GB, Cudic M. TF-containing MUC1 glycopeptides fail to entice Galectin-1 recognition of tumor-associated Thomsen-Freidenreich (TF) antigen (CD176) in solution. Glycoconj J 2020; 37:657-666. [PMID: 33001366 DOI: 10.1007/s10719-020-09951-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/28/2020] [Accepted: 09/25/2020] [Indexed: 12/31/2022]
Abstract
Aberrant Mucin-1 (MUC1) glycosylation with the Thomsen-Friedenreich (TF) tumor-associated antigen (CD176) is a hallmark of epithelial carcinoma progression and poor patient prognosis. Recognition of TF by glycan-binding proteins, such as galectins, enables the pathological repercussions of this glycan presentation, yet the underlying binding specificities of different members of the galectin family is a matter of continual investigation. While Galectin-3 (Gal-3) recognition of TF has been well-documented at both the cellular and molecular level, Galectin-1 (Gal-1) recognition of TF has only truly been alluded to in cell-based platforms. Immunohistochemical analyses have purported Gal-1 binding to TF on MUC1 at the cell surface, however binding at the molecular level was inconclusive. We hypothesize that glycan scaffold (MUC1's tandem repeat peptide sequence) and/or multivalency play a role in the binding recognition of TF antigen by Gal-1. In this study we have developed a method for large-scale expression of Gal-1 and its histidine-tagged analog for use in binding studies by isothermal titration calorimetry (ITC) and development of an analytical method based on AlphaScreen technology to screen for Gal-1 inhibitors. Surprisingly, neither glycan scaffold or multivalent presentation of TF antigen on the scaffold was able to entice Gal-1 recognition to the level of affinity expected for functional significance. Future evaluations of the Gal-1/TF binding interaction in order to draw connections between immunohistochemical data and analytical measurements are warranted.
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Affiliation(s)
- Forrest G FitzGerald
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Maria C Rodriguez Benavente
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA.,Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, 120 E Green St, Athens, GA, 30602, USA
| | - Camelia Garcia
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Yaima Rivero
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - YashoNandini Singh
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA
| | - Hongjie Wang
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL, USA
| | - Gregg B Fields
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, FL, USA.,Department of Chemistry, The Scripps Research Institute/Scripps Florida, Jupiter, FL, USA
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, 33431, USA.
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Singh Y, Kent T, Massetti A, Minond D, Du D, Cudic M. Exploring the Role of Amyloid‐Beta Precursor Protein (APP)
O
‐Glycosylation in Alzheimer’s Disease. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Cudic M, Fields GB. Modulation of receptor binding to collagen by glycosylated 5-hydroxylysine: Chemical biology approaches made feasible by Carpino's Fmoc group. Pept Sci (Hoboken) 2020; 112. [PMID: 33073165 DOI: 10.1002/pep2.24156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The creation of the 9-fluorenylmethoxycarbonyl (Fmoc) group by the Carpino laboratory facilitated the synthesis of peptides containing acid-sensitive groups, such as O-linked glycosides. To fully investigative collagen biochemistry, one needs to assemble peptides that possess glycosylated 5-hydroxylysine (Hyl). A convenient method for the synthesis of Fmoc-Hyl(ε-tert-butyloxycarbonyl (Boc),O-tert-butyldimethylsilyl (TBDMS)) and efficient methods for the synthesis of Fmoc-Hyl[ε-Boc,O-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyl)] have been developed. Glycosylated Fmoc-Hyl derivatives were used to construct a series of types I-IV collagen-model triple-helical peptides (THPs) that incorporated known or proposed receptor binding sites. Glycosylation of Hyl was found to strongly down-regulate the binding of CD44 and the α3β1 integrin to collagen, while the impact on α2β1 integrin binding was more modest. Molecular modeling of integrin binding indicated that Hyl glycosylation directly impacted the association between the α3β1 integrin metal ion-dependent adhesion site (MIDAS) and the receptor binding site within type IV collagen. The Fmoc solid-phase strategy ultimately allowed for chemical biology approaches to be utilized to study tumor cell interactions with glycosylated collagen sequences and document the modulation of receptor interactions by Hyl posttranslational modification.
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Affiliation(s)
- Maré Cudic
- Institute for Human Health & Disease Intervention (I-HEALTH) and the Department of Chemistry & Biochemistry, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458 U.S.A
| | - Gregg B Fields
- Institute for Human Health & Disease Intervention (I-HEALTH) and the Department of Chemistry & Biochemistry, Florida Atlantic University, 5353 Parkside Drive, Jupiter, FL 33458 U.S.A
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Beckwith DM, Cudic M. Tumor-associated O-glycans of MUC1: Carriers of the glyco-code and targets for cancer vaccine design. Semin Immunol 2020; 47:101389. [PMID: 31926647 DOI: 10.1016/j.smim.2020.101389] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 01/01/2020] [Indexed: 02/07/2023]
Abstract
The transformation from normal to malignant phenotype in human cancers is associated with aberrant cell-surface glycosylation. It has frequently been reported that MUC1, the heavily glycosylated cell-surface mucin, is altered in both, expression and glycosylation pattern, in human carcinomas of the epithelium. The presence of incomplete or truncated glycan structures, often capped by sialic acid, commonly known as tumor-associated carbohydrate antigens (TACAs), play a key role in tumor initiation, progression, and metastasis. Accumulating evidence suggests that expression of TACAs is associated with tumor escape from immune defenses. In this report, we will give an overview of the oncogenic functions of MUC1 that are exerted through TACA interactions with endogenous carbohydrate-binding proteins (lectins). These interactions often lead to creation of a pro-tumor microenvironment, favoring tumor progression and metastasis, and tumor evasion. In addition, we will describe current efforts in the design of cancer vaccines with special emphasis on synthetic MUC1 glycopeptide vaccines. Analysis of the key factors that govern structure-based design of immunogenic MUC1 glycopeptide epitopes are described. The role of TACA type, position, and density on observed humoral and cellular immune responses is evaluated.
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Affiliation(s)
- Donella M Beckwith
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, 777 Glades Road, Boca Raton, Florida 33431, United States.
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Singh Y, Rodriguez Benavente MC, Al-Huniti MH, Beckwith D, Ayyalasomayajula R, Patino E, Miranda WS, Wade A, Cudic M. Positional Scanning MUC1 Glycopeptide Library Reveals the Importance of PDTR Epitope Glycosylation for Lectin Binding. J Org Chem 2019; 85:1434-1445. [PMID: 31799848 PMCID: PMC7012140 DOI: 10.1021/acs.joc.9b02396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
One of the main barriers to explaining the functional significance of glycan-based changes in cancer is the natural epitope heterogeneity found on the surface of cancer cells. To help address this knowledge gap, we focused on designing synthetic tools to explore the role of tumor-associated glycans of MUC1 in the formation of metastasis via association with lectins. In this study, we have synthesized for the first time a MUC1-derived positional scanning synthetic glycopeptide combinatorial library (PS-SGCL) that vary in number and location of cancer-associated Tn antigen using the "tea bag" approach. The determination of the isokinetic ratios necessary for the equimolar incorporation of (glyco)amino acids mixtures to resin-bound amino acid was determined, along with developing an efficient protocol for on resin deprotection of O-acetyl groups. Enzyme-linked lectin assay was used to screen PS-SGCL against two plant lectins, Glycine max soybean agglutinin and Vicia villosa. The results revealed a carbohydrate density-dependent affinity trend and site-specific glycosylation requirements for high affinity binding to these lectins. Hence, PS-SGCLs provide a platform to systematically elucidate MUC1-lectin binding specificities, which in the long term may provide a rational design for novel inhibitors of MUC1-lectin interactions involved in tumor spread and glycopeptide-based cancer vaccines.
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Affiliation(s)
- YashoNandini Singh
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Maria C Rodriguez Benavente
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Mohammed H Al-Huniti
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Donella Beckwith
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Ramya Ayyalasomayajula
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Eric Patino
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - William S Miranda
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Alex Wade
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
| | - Maré Cudic
- From the Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science , Florida Atlantic University , 777 Glades Road , Boca Raton , Florida 33431 , United States
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Bionda N, Stawikowski M, Stawikowska R, Cudic M, López-Vallejo F, Treitl D, Medina-Franco J, Cudic P. Inside Cover: Effects of Cyclic Lipodepsipeptide Structural Modulation on Stability, Antibacterial Activity, and Human Cell Toxicity (ChemMedChem 5/2012). ChemMedChem 2012. [DOI: 10.1002/cmdc.201290019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bionda N, Stawikowski M, Stawikowska R, Cudic M, López-Vallejo F, Treitl D, Medina-Franco J, Cudic P. Effects of cyclic lipodepsipeptide structural modulation on stability, antibacterial activity, and human cell toxicity. ChemMedChem 2012; 7:871-82. [PMID: 22392790 PMCID: PMC3500847 DOI: 10.1002/cmdc.201200016] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/09/2012] [Indexed: 11/07/2022]
Abstract
Bacterial infections are becoming increasingly difficult to treat due to the development and spread of antibiotic resistance. Therefore, identifying novel antibacterial targets and new antibacterial agents capable of treating infections by drug-resistant bacteria is of vital importance. The structurally simple yet potent fusaricidin or LI-F class of natural products represents a particularly attractive source of candidates for the development of new antibacterial agents. We synthesized 18 fusaricidin/LI-F analogues and investigated the effects of structure modification on their conformation, serum stability, antibacterial activity, and toxicity toward human cells. Our findings show that substitution of an ester bond in depsipeptides with an amide bond may afford equally potent analogues with improved stability and greatly decreased cytotoxicity. The lower overall hydrophobicity/amphiphilicity of amide analogues in comparison with their parent depsipeptides, as indicated by HPLC retention times, may explain the dissociation of antibacterial activity and human cell cytotoxicity. These results indicate that amide analogues may have significant advantages over fusaricidin/LI-F natural products and their depsipeptide analogues as lead structures for the development of new antibacterial agents.
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Affiliation(s)
- Nina Bionda
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
- Department of Chemistry and BIochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (USA)
| | - Maciej Stawikowski
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
| | - Roma Stawikowska
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
| | - Maré Cudic
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
| | - Fabian López-Vallejo
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
| | - Daniela Treitl
- Department of Chemistry and BIochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431 (USA)
| | - José Medina-Franco
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
| | - Predrag Cudic
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, Florida 34987 (USA), Fax: (+1) 772-345-3649
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Abstract
The synthesis of 5-hydroxylysine (Hyl) derivatives for incorporation by solid-phase methodologies presents numerous challenges. Hyl readily undergoes intramolecular lactone formation, and protected intermediates often have poor solubilities. The goals of this work were twofold: first, develop a convenient method for the synthesis of O-protected Fmoc-Hyl; secondly, evaluate the efficiency of methods for the synthesis of O-glycosylated Fmoc-Hyl. The 5-O-tert-butyldimethylsilyl (TBDMS) fluoren-9-ylmethoxycarbonyl-Hyl (Fmoc-Hyl) derivative was conveniently prepared by the addition of tert-butyldimethylsilyl trifluoromethanesulfonate to copper-complexed Hyl[epsilon-tert-butyloxycarbonyl (Boc)]. The complex was decomposed with Na+ Chelex resin and the Fmoc group added to the alpha-amino group. Fmoc-Hyl(epsilon-Boc, O-TBDMS) was obtained in 67% overall yield and successfully used for the solid-phase syntheses of 3 Hyl-containing peptides. The preparation of Fmoc-Hyl[epsilon-Boc, O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)] was compared for the thioglycoside, trichloroacetimidate and Koenigs-Knorr methods. The most efficient approach was found to be Koenigs-Knorr under inverse conditions, where Fmoc-Hyl(epsilon-Boc)-OBzl and peracetylated galactosyl bromide were added to silver trifluoromethanesulfonate in 1,2-dichloroethane, resulting in a 45% isolated yield. Side-reactions that occurred during previously described preparations of glycosylated Hyl derivatives, such as lactone formation, loss of side-chain protecting groups, orthoester formation, or production of anomeric mixtures, were avoided here. Research on the enzymology of Lys hydroxylation and subsequent glycosylation, as well as the role of glycosylated Hyl in receptor recognition, will be greatly aided by the convenient and efficient synthetic methods developed here.
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Affiliation(s)
- M Cudic
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA
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Abstract
The recent past witnessed a decrease in the number of new antibacterial compounds approved by the regulatory agencies and an almost complete lack of molecules killing bacteria by novel mechanisms of action. The broad spectrum antimicrobial agents currently on the market carry the potential, and indeed victims, of resistance developed against them. The need for new types of antimicrobial drugs coincides with the desire of developing lead molecules that act selectively on a single strain, or perhaps on a few closely related strains. Such selectivity would exclude the likelihood of the emergence of broad-range resistance. Intracellular bacterial targets most prevalently proteins needed for the life cycle of bacteria, carry the potential to be a resourceful target for a new family of antimicrobial compounds. Inhibition of proteinaceous functions requires stereospecificity, and a drug structurally similar to the target proteins themselves. Indeed, some antibacterial peptides show selective inhibition of intracellular targets. A few native peptides and their designed analogs appear to kill only a limited number of bacterial strains. Identification of the binding sites on the target proteins would allow the design of strain-specific antibacterial and antifungal peptides without the fear of development of common resistance to these agents.
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Affiliation(s)
- M Cudic
- The Wistar Institute, Philadelphia, PA 19104, USA
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Robin MA, Anandatheerthavarada HK, Fang JK, Cudic M, Otvos L, Avadhani NG. Mitochondrial targeted cytochrome P450 2E1 (P450 MT5) contains an intact N terminus and requires mitochondrial specific electron transfer proteins for activity. J Biol Chem 2001; 276:24680-9. [PMID: 11325963 DOI: 10.1074/jbc.m100363200] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hepatic mitochondria contain an inducible cytochrome P450, referred to as P450 MT5, which cross-reacts with antibodies to microsomal cytochrome P450 2E1. In the present study, we purified, partially sequenced, and determined enzymatic properties of the rat liver mitochondrial form. The mitochondrial cytochrome P450 2E1 was purified from pyrazole-induced rat livers using a combination of hydrophobic and ion-exchange chromatography. Mass spectrometry analysis of tryptic fragments of the purified protein further ascertained its identity. N-terminal sequencing of the purified protein showed that its N terminus is identical to that of the microsomal cytochrome P450 2E1. In reconstitution experiments, the mitochondrial cytochrome P450 2E1 displayed the same catalytic activity as the microsomal counterpart, although the activity of the mitochondrial enzyme was supported exclusively by adrenodoxin and adrenodoxin reductase. Mass spectrometry analysis of tryptic fragments and also immunoblot analysis of proteins with anti-serine phosphate antibody demonstrated that the mitochondrial cytochrome P450 2E1 is phosphorylated at a higher level compared with the microsomal counterpart. A different conformational state of the mitochondrial targeted cytochrome P450 2E1 (P450 MT5) is likely to be responsible for its observed preference for adrenodoxin and adrenodoxin reductase electron transfer proteins.
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Affiliation(s)
- M A Robin
- Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6047, USA
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Robin MA, Anandatheerthavarada HK, Fang JK, Cudic M, Otvos L, Avadhani NG. Mitochondrial targeted cytochrome P450 2E1 (P450 MT5) contains an intact N terminus and requires mitochondrial specific electron transfer proteins for activity. J Biol Chem 2001. [PMID: 11325963 DOI: 10.1074/jbc.m100363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Hepatic mitochondria contain an inducible cytochrome P450, referred to as P450 MT5, which cross-reacts with antibodies to microsomal cytochrome P450 2E1. In the present study, we purified, partially sequenced, and determined enzymatic properties of the rat liver mitochondrial form. The mitochondrial cytochrome P450 2E1 was purified from pyrazole-induced rat livers using a combination of hydrophobic and ion-exchange chromatography. Mass spectrometry analysis of tryptic fragments of the purified protein further ascertained its identity. N-terminal sequencing of the purified protein showed that its N terminus is identical to that of the microsomal cytochrome P450 2E1. In reconstitution experiments, the mitochondrial cytochrome P450 2E1 displayed the same catalytic activity as the microsomal counterpart, although the activity of the mitochondrial enzyme was supported exclusively by adrenodoxin and adrenodoxin reductase. Mass spectrometry analysis of tryptic fragments and also immunoblot analysis of proteins with anti-serine phosphate antibody demonstrated that the mitochondrial cytochrome P450 2E1 is phosphorylated at a higher level compared with the microsomal counterpart. A different conformational state of the mitochondrial targeted cytochrome P450 2E1 (P450 MT5) is likely to be responsible for its observed preference for adrenodoxin and adrenodoxin reductase electron transfer proteins.
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Affiliation(s)
- M A Robin
- Department of Animal Biology and the Mari Lowe Center for Comparative Oncology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6047, USA
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Ducrocq C, Servy C, Cudic M, Blanchard EB. [Intervention by nitric oxide, NO, and its oxide derivatives particularly in mammals]. Can J Physiol Pharmacol 2001; 79:95-102. [PMID: 11235675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Nitric oxide (NO) is a natural and stable free radical produced in soil and water by the bacteriological reduction of nitrites and nitrates and in animals by the enzyme oxidation of L-arginine. NO is biosynthesised by finely regulated enzymatic systems called NO-synthases and readily diffuses through tissues. It reacts rapidly with hemoproteins and iron-sulphur centers to form nitrosylated compounds. It oxidises more slowly to form nitrogen oxides that nitrosate thiols into thionitrite. NO is transported in these various forms and released spontaneously or through yet unclear mechanisms into most cells; it also regulates oxygen consumption at the mitochondrial respiratory chain level through interaction with cytochrome oxidase. In the cardiovascular system, NO lowers blood pressure by activating a hemoprotein, the guanylate cyclase present in muscle cells; through such interaction it acts also as a neuromediator and neuromodulator in the nervous system. However, many of NO's roles result from rapid coupling to other radicals; for example, it reacts with the superoxide anion (O2-) to form oxoperoxinitrate (ONOO-, also known as peroxynitrite). This strong oxidant of metallic centers, thiols, and antioxidants is also able to convert tyrosine to 3-nitrotyrosine and to act upon tyrosine residues contained in proteins. The biological aspects of the roles of NO are presented with particular respect to the rapid interactions of NO with hemoproteins' iron and other radicals. Concurrently, NO oxidation enables nitrosation reactions primarily of thiols but ultimately of nucleic bases. The thionitrite function (R-S-NO) thus formed and the dimerisation and nitration of tyrosine residues are protein post-translational modifications that are being investigated in animals.
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Affiliation(s)
- C Ducrocq
- Institut de Chimie des Substances Naturelles, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France.
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Abstract
To investigate the protective effect of the anesthetic 2, 6-diisopropylphenol, or propofol, in oxidative processes in which (*)NO and peroxynitrite are involved, direct interactions were explored. The reactions of the highly lipophilic propofol with (*)NO in methanolic or aqueous buffered solutions under air were shown to produce the same compounds as those detected with peroxynitrite, but with very low yields and slow rates. In aqueous neutral medium, peroxynitrite (ONOO(-), ONOOCO(-)(2), ONOOH) was able to nitrate and oxidize propofol: In addition to oxidation products, quinone and quinone dimer, the formation of the 4-nitropropofol derivative was detected, increasing with peroxynitrite or CO(2) concentrations. Nitration reached 20% after the addition of 25 mM bicarbonate to an equimolecular mixture of peroxynitrite and propofol in methanol/phosphate-buffered solution (1/4,v/v) at pH 7.4. However, peroxynitrite either in methanol or in alkaline-buffered mixture (optimum pH 10-12) resulted in the rapid and almost complete transformation of propofol to an intermediate compound 1, which further decomposed to 4-nitrosopropofol. The transient compound 1 was obtained from either peroxynitrite or (*)NO in the presence of oxygen. From mass spectrometry determination of compound 1 we propose the involvement of the nitrosodioxyl radical ONOO(*), forming an adduct with the propofoxyl radical, to yield 4-nitrosodioxypropofol and finally 4-nitrosopropofol.
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Affiliation(s)
- M Cudic
- Institut de Chimie des Substances Naturelles, CNRS, Avenue de la Terrasse, Gif sur Yvette, F-91198, France
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Cudic M, Bulet P, Hoffmann R, Craik DJ, Otvos L. Chemical synthesis, antibacterial activity and conformation of diptericin, an 82-mer peptide originally isolated from insects. Eur J Biochem 1999; 266:549-58. [PMID: 10561597 DOI: 10.1046/j.1432-1327.1999.00894.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The small amounts of antibacterial peptides that can be isolated from insects do not allow detailed studies of their range of activity, side-chain sugar requirements, or their conformation, factors that frequently play roles in the mode of action. In this paper, we report the solid-phase step-by-step synthesis of diptericin, an 82-mer peptide, originally isolated from Phormia terranovae. The unglycosylated peptide was purified to homogeneity by conventional reversed-phase high performance liquid chromatography, and its activity spectrum was compared to that of synthetic unglycosylated drosocin, which shares strong sequence homology with diptericin's N-terminal domain. Diptericin appeared to have antibacterial activity for only a limited number of Gram-negative bacteria. Diptericin's submicromolar potency against Escherichia coli strains indicated that, in a manner similar to drosocin, the presence of the carbohydrate side chain is not necessary to kill bacteria. Neither the N-terminal, drosocin-analog fragment, nor the C-terminal, glycine-rich attacin-analog region was active against any of the bacterial strains studied, regardless of whether the Gal-GalNAc disaccharide units were attached. This suggested that the active site of diptericin fell outside the drosocin or attacin homology domains. In addition, the conformation of diptericin did not seem to play a role in the antibacterial activity, as was demonstrated by the complete lack of ordered structure by two-dimensional nuclear magnetic resonance spectroscopy and circular dichroism. Diptericin completely killed bacteria within 1 h, considerably faster than drosocin and the attacins; unlike some other, fast-acting antibacterial peptides, diptericin did not lyse normal mammalian cells. Taken together, these data suggest diptericin does not belong to any known class of antibacterial peptides.
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Affiliation(s)
- M Cudic
- The Wistar Institute, Philadelphia, PA 19104, USA
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Cudic M, Dendane M, Houé-Levin C, Ducrocq C. Nitration of angiotensin II by .NO2 radicals and peroxynitrite. .NO protects against .NO2 radical reaction. Eur J Biochem 1999; 265:967-71. [PMID: 10518791 DOI: 10.1046/j.1432-1327.1999.00798.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To react with peptides, nitric oxide.NO has to be activated by oxidation, or by coupling with superoxide (O.-2) thereby producing peroxynitrite. In the course of.NO oxidation,.NO2 free radicals and N2O3 may be formed. Using gamma-irradiation methods, we characterized the products formed by these nitrogen oxides with angiotensin II. Angiotensin II is specifically nitrated at its tyrosinyl residue by.NO2 or peroxynitrite. Equimolecular amounts of each reagent in K+/Pi solutions at pH 7.4 led to 56% and 5% nitration yields, respectively. Nitrogen oxides produced by autoxidation of.NO, as well as.NO2 under.NO, reacted only with the arginine residue, giving a mixture of peptides containing citrulline, a N-(hydroxylamino-cyanamido-) instead of guanido group, and a conjugated diene derived from an arginine side-chain. However, nitrosation reactions by N2O3 occurred only when the initial concentration of.NO2 was 10 times that able to react with angiotensin II. Thus, in this case.NO appears to protect against.NO2 action.
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Affiliation(s)
- M Cudic
- Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France
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