Conformational dynamics in glutathione reductase

摘要

Time-resolved polarized fluorescence decays of FAD bound to glutathione reductase have been obtained upon separate excitation at 457.9 nm and 514.5 nm. From the inverse Laplace transform of the fluorescence decays as obtained by the maximum entropy method, five enzyme conformers can be distinguished in solution. By red-edge and main-band excitation we demonstrate that intersubunit energy transfer occurs between the flavin prosthetic groups as well as restricted motion of flavin. From a 2-D maximum entropy analysis, it can be deduced that the observed conformers of glutathione reductase have different dynamic properties. The ability of the maximum entropy method to resolve a heterogeneous population of emitters with distinct dynamical properties is tested by simulated data. From the results, a role in catalysis is proposed to equilibrium fluctuations in glutathione reductase.