Atypical bacilliredoxin abxc plays a role in responding to oxidative stress in radiation-resistant bacterium deinococcus radiodurans

Soyoung Jeong, Jong Hyun Jung, Min Kyu Kim, Arjan de Groot, Laurence Blanchard, Sangryeol Ryu, Yong Sun Bahn, Sangyong Lim

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


Deinococcus radiodurans is a robust bacterium with extraordinary resistance to ionizing radiation and reactive oxygen species (ROS). D. radiodurans produces an antioxidant thiol compound called bacillithiol (BSH), but BSH-related enzymes have not been investigated. The D. radiodurans mutant lacking bshA (dr_1555), the first gene of the BSH biosynthetic pathway, was devoid of BSH and sensitive to hydrogen peroxide (H2O2 ) compared to the wild-type D. radiodurans strain. Three bacilliredoxin (Brx) proteins, BrxA, B, and C, have been identified in BSH-producing bacteria, such as Bacillus. D. radiodurans possesses DR_1832, a putative homolog of BrxC. However, because DR_1832 contains a novel signature motif (TCHKT) and a C-terminal region similar to the colicin-like immunity domain, we named it AbxC (atypical BrxC). The deletion of abxC also sensitized cells to H2O2 . AbxC exhibited peroxidase activity in vitro, which was linked to nicotinamide adenine dinucleotide phosphate (NADPH) oxidation via the BSH disulfide reductase DR_2623 (DrBdr). AbxC proteins were present mainly as dimers after exposure to H2O2 in vitro, and the oxidized dimers were resolved to monomers by the reaction coupled with BSH as an electron donor, in which DrBdr transported reducing equivalents from NADPH to AbxC through BSH recycling. We identified 25 D. radiodurans proteins that potentially interact with AbxC using AbxC-affinity chromatography. Most of them are associated with cellular metabolisms, such as glycolysis and amino acid biosynthesis, and stress response. Interestingly, AbxC could bind to the proposed peroxide-sensing transcription regulator, DrOxyR. These results suggest that AbxC may be involved in the H2O2 signaling mechanism mediated by DrOxyR.

Original languageEnglish
Article number1148
Issue number7
Publication statusPublished - 2021 Jul

Bibliographical note

Funding Information:
Funding: This research was supported by the Nuclear R&D program and the National Research Foundation of Korea (NRF) grant (No.2020K1A3A1A21039740) funded by the Ministry of Science and ICT (MSIT), Republic of Korea.

Publisher Copyright:
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Physiology
  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology


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