Journal article
Preferred peptide backbone conformations in the unfolded state revealed by the structure analysis of alanine-based (AXA) tripeptides in aqueous solution
Proceedings of the National Academy of Sciences - PNAS, v 101(27), pp 10054-10059
06 Jul 2004
PMID: 15220481
Featured in Collection : UN Sustainable Development Goals @ Drexel
Abstract
We have combined Fourier transform IR, polarized Raman spectroscopy, and vibrational CD measurements of the amide I' band profile of alanyl-X-alanine tripeptides in (2)H(2)O to obtain the dihedral angles of their central amino acid residue. X represents glycine, valine, methionine, histidine, serine, proline, lysine, leucine, tryptophan, tyrosine, and phenylalanine. The experimental data were analyzed by means of a recently developed algorithm, which exploits the excitonic coupling between the amide modes of the two peptide groups. The results were checked by measuring the respective electronic CD spectra. The investigated peptides can be sorted into three classes. Valine, phenylalanine, tryptophan, histidine, and serine predominantly adopt an extended beta-strand conformation. Cationic lysine and proline prefer a polyproline II-like structure. Alanine, methionine, glycine, and leucine populate these two conformations with comparable probability. Our results are in variance with the prediction of the random-coil model, but supportive of Flory's isolated-pair hypothesis. We combined the obtained structural propensities of the investigated residues and similar information about other residues in the literature (i.e., glutamate, aspartate, isoleucine, and glutamine) to predict possible conformations of the monomeric amyloid beta peptide A beta(1-42) in aqueous solution, which reproduces results from most recent spectroscopic studies. Thus, it is demonstrated that the unfolded state of peptides can be understood in terms of the intrinsic structural propensities of their amino acid residues.
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Details
- Title
- Preferred peptide backbone conformations in the unfolded state revealed by the structure analysis of alanine-based (AXA) tripeptides in aqueous solution
- Creators
- Fatma Eker - Department of Chemistry, University of Puerto Rico, Río Piedras Campus, P.O. Box 23346, San Juan PR00931, Puerto RicoKai GriebenowXiaolin CaoLaurence A NafieReinhard Schweitzer-Stenner
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, v 101(27), pp 10054-10059
- Publisher
- PNAS; United States
- Grant note
- P20 RR16439-01 / NCRR NIH HHS P20 RR016439 / NCRR NIH HHS
- Resource Type
- Journal article
- Language
- English
- Academic Unit
- Chemistry
- Web of Science ID
- WOS:000222534200021
- Scopus ID
- 2-s2.0-3042750640
- Other Identifier
- 991014878065104721
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- Collaboration types
- Domestic collaboration
- Web of Science research areas
- Biochemistry & Molecular Biology