7AAW

Thioredoxin Reductase from Bacillus cereus

Summary for 7AAW

• Entry DOI: 10.2210/pdb7aaw/pdb
• Descriptor: Thioredoxin reductase, FLAVIN-ADENINE DINUCLEOTIDE, alpha-D-glucopyranose, ... (7 entities in total)
• Functional Keywords: disulfide reductase, fad, flavoprotein, nadph, oxidoreductase
• Biological source: Bacillus cereus (strain ATCC 14579 / DSM 31 / JCM 2152 / NBRC 15305 / NCIMB 9373 / NRRL B-3711)
• Total number of polymer chains: 2
• Total formula weight: 73114.54

Authors

Shoor, M.,Gudim, I.,Hersleth, H.-P.,Hammerstad, M. (deposition date: 2020-09-04, release date: 2021-09-15, Last modification date: 2024-10-23)

Primary citation

Shoor, M.,Gudim, I.,Hersleth, H.P.,Hammerstad, M.
Thioredoxin reductase from Bacillus cereus exhibits distinct reduction and NADPH-binding properties.
Febs Open Bio, 11:3019-3031, 2021

PubMed Abstract: Low-molecular-weight (low M ) 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 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.

PubMed: 34492167
DOI: 10.1002/2211-5463.13289

Experimental method

X-RAY DIFFRACTION (2.25 Å)