High pressure reveals structural determinants for globin hexacoordination: neuroglobin and myoglobin cases

L. CAPECE; M.A. MARTI; A. BIDON CHANAL; A. NADRA; F.J. LUQUE; D.A. ESTRIN

PROTEINS: STRUCTURE, FUNCTION AND GENETICS

Wiley

Año: 2009 vol. 75 p. 885 - 894

0887-3585

The influence of pressure on the equilibrium betweenfive-(5c) and six-coordination (6c) forms in neuroglo-bin (Ngb) and myoglobin (Mb) has been examined bymeans of molecular dynamics (MD) simulations at nor-mal and high pressure. The results show that the maineffect of high pressure is to reduce the protein mobilitywithout altering the structure in a significant manner.Moreover, our data suggest that the equilibrium between5c and 6c states in globins is largely controlled by thestructure and dynamics of the C-D region. Finally, inagreement with the available experimental data, the freeenergy profiles obtained from steered MD for bothproteins indicate that high pressure enhances hexacoordination. In Ngb, the shift in equilibrium is mainly related to an increase in the 6c?5ctransition barrier, whereas in Mb such a shift is primarilydue to a destabilization of the 5c state.