Related Experiment Video
Updated: Mar 29, 2026

Quantifying the Binding Interactions Between CuII and Peptide Residues in the Presence and Absence of Chromophores
Published on: April 5, 2022
Temperature Effects on Donor-Acceptor Couplings in Peptides. A Combined Quantum Mechanics and Molecular Dynamics
Frank H Wallrapp1, Alexander A Voityuk1, Victor Guallar1
1Barcelona Supercomputing Center, Nexus II Building, 08028 Barcelona, Spain, Institute of Computational Chemistry, University of Girona, 17071 Girona, Spain, and Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain.
Abstract:
We report a quantum chemistry and molecular dynamics study on the temperature dependence of electronic coupling in two short model oligopeptides. Ten nanoseconds replica exchange molecular dynamics was performed on Trp-(Pro)3-Trp and Trp-(Pro)6-Trp peptides in the gas phase in combination with computation of the energy and electronic coupling for thermal hole transfer between Trp residues. The electron transfer parameters were estimated by using the semiempirical INDO/S method together with the charge fragment difference scheme. Conformational analysis of the derived trajectories revealed that the electronic coupling becomes temperature dependent when incorporating structural dynamics of the system. We demonstrate that Trp-(Pro)3-Trp, having only few degrees of freedom, results in relatively weak couplings at low and high temperature and a strong peak at 144 K, whereas the more flexible system Trp-(Pro)6-Trp shows monotonically decreased coupling. Only a few conformations with strong donor-acceptor couplings are shown to be crucial for the overall ET rates. Our results introduce the question whether the T dependence of ET coupling can also be found in large biological systems.
Related Concept Videos
Peptide Bonds
Phase Transitions: Melting and Freezing
Diels–Alder vs Retro-Diels–Alder Reaction: Thermodynamic Factors
Noncovalent Attractions in Biomolecules
Four types of noncovalent interactions are hydrogen bonds, van der Waals forces, ionic bonds, and hydrophobic interactions.
Hydrogen bonding results from the electrostatic attraction of a hydrogen atom covalently bonded to a strong-electronegative atom like oxygen,...
Complexation Equilibria: The Chelate Effect
Protein Denaturation

