Folding molecular dynamics simulation of T-peptide, a HIV viral entry inhibitor : Structure, dynamics, and comparison with the experimental data

TL;DR

This study used molecular dynamics simulations to analyze the structure and dynamics of the HIV entry-inhibiting peptide T, validating the results with experimental NMR data, revealing its flexible nature and preferred beta-turn conformation.

Contribution

The paper provides a detailed molecular dynamics analysis of peptide T, correlating simulation results with experimental NMR data to validate its structural and dynamical properties.

Findings

Peptide T is highly flexible with rapid interconverting structures.

The C-terminal region tends to form a stable beta-turn.

Simulation results agree well with experimental NMR data.

Abstract

Peptide T is a synthetic octapeptide fragment, which corresponds to the region 185-192 of the gp120 HIV coat protein and functions as a viral entry inhibitor. In this work, a folding molecular dynamics simulation of peptide T in a membrane-mimicking (DMSO) solution was performed with the aim of characterizing the peptide's structural and dynamical properties. We show that peptide T is highly flexible and dynamic. The main structural characteristics observed were rapidly interconverting short helical stretches and turns, with a notable preference for the formation of $\beta$-turns. The simulation also indicated that the C-terminal part appears to be more stable than the rest of the peptide, with the most preferred conformation for residues 5-8 being a $\beta$-turn. In order to validate the accuracy of the simulations, we compared our results with the experimental NMR data obtained for the T-peptide in the same solvent. In agreement with the simulation, the NMR data indicated the presence of a preferred structure in solution that was consistent with a $\beta$-turn comprising the four C-terminal residues. An additional comparison between the experimental and simulation-derived chemical shifts also showed a reasonable agreement between experiment and simulation, further validating the simulation-derived structural characterization of the T-peptide.