Ferric reductase B (FerB) is a flavin mononucleotide (FMN)-containing NAD(P)H:acceptor oxidoreductase structurally close to the Gluconacetobacter hansenii chromate reductase (ChrR). The crystal structure of ChrR was previously determined with a chloride bound proximal to FMN in the vicinity of Arg101, and the authors suggested that the anionic electron acceptors, chromate and uranyl tricarbonate, bind similarly. Here, we identify the corresponding arginine residue in FerB (Arg95) as being important for the reaction of FerB with superoxide. Four mutants at position 95 were prepared and found kinetically to have impaired capacity for superoxide binding. Stopped-flow data for the flavin cofactor showed that the oxidative step is rate limiting for catalytic turnover. The findings are consistent with a role for FerB as a superoxide scavenging contributor.

• MeSH
• arginin genetika   MeSH
• flavinmononukleotid chemie   genetika   MeSH
• flaviny genetika   metabolismus   MeSH
• FMN-reduktasa chemie   genetika   MeSH
• katalytická doména genetika   MeSH
• kinetika MeSH
• konformace proteinů * MeSH
• krystalografie rentgenová MeSH
• oxidace-redukce MeSH
• oxidoreduktasy chemie   genetika   MeSH
• Paracoccus denitrificans chemie   enzymologie   MeSH
• sekvence aminokyselin genetika   MeSH
• superoxidy metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH