Symmetric Allosteric Mechanism of Hexameric Escherichia coli Arginine Repressor Exploits Competition between L-Arginine Ligands and Resident Arginine Residues

0359496 - ÚVGZ 2012 RIV US eng J - Journal Article
Strawn, R. - Melicherčík, Milan - Green, M. - Stockner, T. - Carey, J. - Ettrich, Rüdiger
Symmetric Allosteric Mechanism of Hexameric Escherichia coli Arginine Repressor Exploits Competition between L-Arginine Ligands and Resident Arginine Residues.
PLoS Computational Biology. Roč. 6, č. 6 (2010), s. 1-12. ISSN 1553-734X. E-ISSN 1553-7358
R&D Projects: GA MŠMT(CZ) LC06010; GA ČR GAP207/10/1934
Institutional research plan: CEZ:AV0Z60870520
Keywords : molecular-dynamics simulations * free-energy calculations * structural basis * DNA-binding domain * bacillus-stearothermophilus * T4 lysozyme * proteins * hemoglobin * model * affinity
Subject RIV: EH - Ecology, Behaviour
Impact factor: 5.515, year: 2010

A controversial prediction of the famous allostery model of Monod, Wyman, and Changeux is that constraints imposed on protein subunits by multimerization are relaxed by ligand binding, but with conservation of symmetry in partially-liganded states. Interpretation of thermodynamic ligand-binding data through the lens of molecular dynamics simulation has led to structural and energetic description of such a state for the hexameric Escherichia coli arginine repressor, which displays strong negative cooperativity of L-arginine binding. The results indicate that partially-liganded states can be structurally symmetric despite their conceptual asymmetry. The symmetric relaxed state is visualized as a multimer with all subunits anchored near the center, and with motions transferred to the periphery of the assembly. Thus, even during sequential filling of binding sites, symmetry can be maintained by exploiting the dynamics of the assembly and the distributed nature of its cohesive free energy.
Permanent Link: http://hdl.handle.net/11104/0197277