Multiphoton Absorption of Myoglobin–Nitric Oxide Complex: Relaxation by D-NEMD of a Stationary State

摘要

ABSTRACT:udThe photodissociation and geminate recombination of nitric oxide inudmyoglobin, under continuous illumination, is modeled computationally. Theudrelaxation of the photon energy into the protein matrix is also considered in audsingle simulation scheme that mimics a complete experimental setup. The dynamicudapproach to non-equilibrium molecular dynamics is used, starting from a steadyudstate, to compute its relaxation to equilibrium. Simulations are conducted for theudnative form of sperm whale myoglobin and for two other mutants, V68W and L29F,udillustrating a fair diversity of spatial and temporal geminate recombination processes.udEnergy flow to the heme and immediate protein environment provide hints toudallostery. In particular, a pathway of energy flow between the heme and the FG loopudis illustrated. Although the simulations were conducted for myoglobin only, the thermal fluctuations of the FG corner are inudagreement with the large structural shifts of FG during the allosteric transition of tetrameric hemoglobin.