Journal article
Disorder and order in unfolded and disordered peptides and proteins: A view derived from tripeptide conformational analysis. II. Tripeptides with short side chains populating asx and beta-type like turn conformations
Proteins, structure, function, and bioinformatics, v 81(6), pp 968-983
01 Jun 2013
PMID: 23229867
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
In the preceding paper, we found that ensembles of tripeptides with long or bulky chains can include up to 20% of various turns. Here, we determine the structural and thermodynamic characteristics of GxG peptides with short polar and/or ionizable central residues (D, N, C), whose conformational distributions exhibit higher than average percentage (>20%) of turn conformations. To probe the side-chain conformations of these peptides, we determined the 3J(H,H) coupling constants and derived the population of three rotamers with 1-angles of 60 degrees, 180 degrees and 60 degrees, which were correlated with residue propensities by DFT-calculations. For protonated GDG, the rotamer distribution provides additional evidence for asx-turns. A comparison of vibrational spectra and NMR coupling constants of protonated GDG, ionized GDG, and the protonated aspartic acid dipeptide revealed that side chain protonation increases the pPII content at the expense of turn populations. The charged terminal groups, however, have negligible influence on the conformational properties of the central residue. Like protonated GDG, cationic GCG samples asx-turns to a significant extent. The temperature dependence of the UVCD spectra and 3J(HNH) constants suggest that the turn populations of GDG and GNG are practically temperature-independent, indicating enthalpic and entropic stabilization. The temperature-independent J-coupling and UVCD spectra of GNG require a three-state model. Our results indicate that short side chains with hydrogen bonding capability in GxG segments of proteins may serve as hinge regions for establishing compact structures of unfolded proteins and peptides. Proteins 2013. (c) 2012 Wiley Periodicals, Inc.
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Details
- Title
- Disorder and order in unfolded and disordered peptides and proteins: A view derived from tripeptide conformational analysis. II. Tripeptides with short side chains populating asx and beta-type like turn conformations
- Creators
- Karin Rybka - Goethe University FrankfurtSiobhan E. Toal - Drexel UniversityDaniel J. Verbaro - Drexel UniversityDaniel Mathieu - Goethe University FrankfurtHarald Schwalbe - Goethe University FrankfurtReinhard Schweitzer-Stenner - Drexel University
- Publication Details
- Proteins, structure, function, and bioinformatics, v 81(6), pp 968-983
- Publisher
- Wiley
- Number of pages
- 16
- Grant note
- Chem 0939972 / National Science Foundation; National Science Foundation (NSF) DFG; German Research Foundation (DFG); European Commission
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- [Retired Faculty]; Chemistry
- Web of Science ID
- WOS:000319349200005
- Scopus ID
- 2-s2.0-84878156947
- Other Identifier
- 991019167975604721
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- Collaboration types
- Domestic collaboration
- International collaboration
- Web of Science research areas
- Biochemistry & Molecular Biology
- Biophysics