Arginine-95 is important for recruiting superoxide to the active site of the FerB flavoenzyme of Paracoccus denitrificans
Language English Country Great Britain, England Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
Grant support
16-18476S
Czech Science Foundation (Grantová agentura České republiky) - International
- Keywords
- Paracoccus denitrificans, antioxidant enzyme, chromate reductase, flavoprotein, superoxide reductase,
- MeSH
- Arginine genetics MeSH
- Flavin Mononucleotide chemistry genetics MeSH
- Flavins genetics metabolism MeSH
- FMN Reductase chemistry genetics MeSH
- Catalytic Domain genetics MeSH
- Kinetics MeSH
- Protein Conformation * MeSH
- Crystallography, X-Ray MeSH
- Oxidation-Reduction MeSH
- Oxidoreductases chemistry genetics MeSH
- Paracoccus denitrificans chemistry enzymology MeSH
- Amino Acid Sequence genetics MeSH
- Superoxides metabolism MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Arginine MeSH
- chromate reductase MeSH Browser
- ferric citrate iron reductase MeSH Browser
- Flavin Mononucleotide MeSH
- Flavins MeSH
- FMN Reductase MeSH
- Oxidoreductases MeSH
- Superoxides MeSH
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.
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