Peptide conformational heterogeneity revealed from nonlinear vibrational spectroscopy and molecular-dynamics simulations

Woutersen, Sander, Pfister, Rolf, Hamm, Peter, Mu, Yuguang, Kosov, Daniel S., and Stock, Gerhard (2002) Peptide conformational heterogeneity revealed from nonlinear vibrational spectroscopy and molecular-dynamics simulations. Journal of Chemical Physics, 117 (14). pp. 6833-6840.

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Abstract

Nonlinear time-resolved vibrational spectroscopy is used to compare spectral broadening of the amide I band of the small peptide trialanine with that of N-methylacetamide, a commonly used model system for the peptide bond. In contrast to N-methylacetamide, the amide I band of trialanine is significantly inhomogeneously broadened. Employing classical molecular-dynamics simulations combined with density-functional-theory calculations, the origin of the spectral inhomogeneity is investigated. While both systems exhibit similar hydrogen-bonding dynamics, it is found that the conformational dynamics of trialanine causes a significant additional spectral broadening. In particular, transitions between the poly(Gly)II and the αR conformations are identified as the main source of the additional spectral inhomogeneity of trialanine. The experimental and computational results suggest that trialanine adopts essentially two conformations: poly(Gly)II (80%) and αR (20%). The potential of the joint experimental and computational approach to explore conformational dynamics of peptides is discussed.

Item ID: 27287
Item Type: Article (Research - C1)
ISSN: 1089-7690
Date Deposited: 24 Jun 2013 00:18
FoR Codes: 02 PHYSICAL SCIENCES > 0299 Other Physical Sciences > 029901 Biological Physics @ 50%
03 CHEMICAL SCIENCES > 0307 Theoretical and Computational Chemistry > 030701 Quantum Chemistry @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970102 Expanding Knowledge in the Physical Sciences @ 100%
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