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Title: Protein Under Pressure: Molecular Dynamics Simulation of the Arc Repressor

Experimental nuclear magnetic resonance results for the Arc Repressor have shown that this dimeric protein dissociates into a molten globule at high pressure. This structural change is accompanied by a modification of the hydrogenbonding pattern of the intermolecular -sheet: it changes its character from intermolecular to intramolecular with respect to the two monomers. Molecular dynamics simulations of the Arc Repressor, as a monomer and a dimer, at elevated pressure have been performed with the aim to study this hypothesis and to identify the major structural and dynamical changes of the protein under such conditions. The monomer appears less stable than the dimer. However, the complete dissociation has not been seen because of the long timescale needed to observe this phenomenon. In fact, the protein structure altered very little when increasing the pressure. It became slightly compressed and the dynamics of the side-chains and the unfolding process slowed down. Increasing both, temperature and pressure, a tendency of conversion of intermolecular into intramolecular hydrogen bonds in the -sheet region has been detected, supporting the mentioned hypothesis. Also, the onset of denaturation of the separated chains was observed.
Authors:
; ;
Publication Date:
OSTI Identifier:
920552
Report Number(s):
PNNL-SA-51875
TRN: US200818%%702
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Proteins. Structure, Function, and Bioinformatics, 65(1):136-144; Journal Volume: 65; Journal Issue: 1
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; BONDING; CHAINS; DISSOCIATION; HYDROGEN; HYPOTHESIS; MODIFICATIONS; MONOMERS; NUCLEAR MAGNETIC RESONANCE; PROTEIN STRUCTURE; PROTEINS; SIMULATION