Oxygen affinity controlled by dynamical distal conformations: The soybean leghemoglobin and the Paramecium caudatum hemoglobin cases

M.A. MARTI; L. CAPECE; D.E. BIKIEL; B. FALCONE; D.A. ESTRIN

PROTEINS: STRUCTURE, FUNCTION AND GENETICS

Wiley

Año: 2007 vol. 68 p. 480 - 487

0887-3585

The binding of diatomic ligands, such as O2, NO, and CO, to heme proteins is a process intimately related with their function. In this work, we analyzed by means of a combination of classical Molecular Dynamics (MD) and Hybrid Quantum-Classical (QM/MM) techniques the existence of multiple conformations in the distal site of heme proteins and their influence on oxygen affinity regulation. We considered two representative examples: soybean leghemoglobin (Lba) and Paramecium caudatum truncated hemoglobin (PcHb). The results presented in this work provide a molecular interpretation for the kinetic, structural, and mutational data that cannot be obtained by assuming a single distal conformation. © 2007 Wiley-Liss, Inc.