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

Lugar: New Jersey; Año: 2007 vol. 67 p. 480 - 487

0887-3585

The binding of diatomic ligands, such as O2, NO, and CO to heme proteins is a process intimately related to 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 provede a molecular interpretation for the kinetic, structural, and mutational data that cannot be obtained by assuming a single distal conformation.