Premium
Deletion of the autoregulatory insert modulates intraprotein electron transfer in rat neuronal nitric oxide synthase
Author(s) -
Feng Changjian,
Roman Linda J.,
Hazzard James T.,
Ghosh Dipak K.,
Tollin Gordon,
Masters Bettie Sue S.
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.07.005
Subject(s) - electron transfer , insert (composites) , chemistry , calmodulin , kinetics , nitric oxide synthase , neuronal nitric oxide synthase , biophysics , mutant , nitric oxide , atp synthase , limiting , reaction rate constant , heme , photochemistry , biochemistry , biology , enzyme , materials science , mechanical engineering , physics , organic chemistry , quantum mechanics , gene , engineering , composite material
Comparative CO photolysis kinetics studies on wild‐type and autoregulatory (AR) insert‐deletion mutant of rat nNOS holoenzyme were conducted to directly investigate the role of the unique AR insert in the catalytically significant FMN–heme intraprotein electron transfer (IET). Although the amplitude of the IET kinetic traces was decreased two‐ to three‐fold, the AR deletion did not change the rate constant for the calmodulin‐controlled IET. This suggests that the rate‐limiting conversion of the electron‐accepting state to a new electron‐donating (output) state does not involve interactions with the AR insert, but that AR may stabilize the output state once it is formed.