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Deletion of the autoregulatory insert modulates intraprotein electron transfer in rat neuronal nitric oxide synthase.

ABSTRACT: 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.

SUBMITTER: Feng C

PROVIDER: S-EPMC2574637 | biostudies-literature | 2008 Aug

REPOSITORIES: biostudies-literature

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Deletion of the autoregulatory insert modulates intraprotein electron transfer in rat neuronal nitric oxide synthase.

Feng Changjian C Roman Linda J LJ Hazzard James T JT Ghosh Dipak K DK Tollin Gordon G Masters Bettie Sue S BS

FEBS letters 20080714 18

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 ...[more]

PMID: 18625229

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