Thioredoxin reductase from Bacillus cereus exhibits distinct reduction and NADPH‐binding properties
| Autor: | Hans-Petter Hersleth, Marta Hammerstad, Marita Shoor, Ingvild Gudim |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
inorganic chemicals
crystal structure Thioredoxin-Disulfide Reductase Flavodoxin QH301-705.5 Thioredoxin reductase Crystallography X-Ray ribonucleotide reductase General Biochemistry Genetics and Molecular Biology flavodoxin reductase Thioredoxins Bacillus cereus Bacterial Proteins Ribonucleotide Reductases Binding site Biology (General) Research Articles Ferredoxin Binding Sites biology Chemistry thioredoxin reductase biology.organism_classification Ferredoxin-NADP Reductase Ribonucleotide reductase Biochemistry Cereus biology.protein NADPH binding bacteria Thioredoxin Oxidation-Reduction NADP Research Article |
| Zdroj: | FEBS Open Bio, Vol 11, Iss 11, Pp 3019-3031 (2021) 'FEBS Open Bio ', vol: 11, pages: 3019-3031 (2021) FEBS Open Bio |
| ISSN: | 2211-5463 |
| Popis: | Low‐molecular‐weight (low M r) thioredoxin reductases (TrxRs) are homodimeric NADPH‐dependent dithiol flavoenzymes that reduce thioredoxins (Trxs) or Trx‐like proteins involved in the activation networks of enzymes, such as the bacterial class Ib ribonucleotide reductase (RNR). During the last few decades, TrxR‐like ferredoxin/flavodoxin NADP+ oxidoreductases (FNRs) have been discovered and characterized in several types of bacteria, including those not encoding the canonical plant‐type FNR. In Bacillus cereus, a TrxR‐like FNR has been shown to reduce the flavodoxin‐like protein NrdI in the activation of class Ib RNR. However, some species only encode TrxR and lack the homologous TrxR‐like FNR. Due to the structural similarity between TrxRs and TrxR‐like FNRs, as well as variations in their occurrence in different microorganisms, we hypothesized that low M r TrxR may be able to replace TrxR‐like FNR in, for example, the reduction of NrdI. In this study, characterization of TrxR from B. cereus has revealed a weak FNR activity toward NrdI reduction. Additionally, the crystal structure shows that only one out of two binding sites of the B. cereus TrxR homodimer is occupied with NADPH, indicating a possible asymmetric co‐substrate binding in TrxR. Bacillus cereus thioredoxin reductase (TrxR) reveals weak activity as a reductase of the flavodoxin‐like protein NrdI, as compared to the endogenous NrdI‐reductase ferredoxin/flavodoxin NADP+ oxidoreductase (FNR). A TrxR mutant, designed to resemble FNR, did not improve the catalytic efficiency. The crystal structure of homodimeric B. cereus TrxR shows a single bound NADPH, indicating a possible asymmetric co‐substrate binding in TrxR. |
| Databáze: | OpenAIRE |
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