pISSN 2288-6982
eISSN 2288-7105




BioDesign 2023; 11(3): 39-44

Published online September 30, 2023

© Korean Society for Structural Biology

Crystal structure of the putative HOCl and HOSCN-responsive peroxiredoxin RclX from Pseudomonas aeruginosa

Nayeon Ki1,‡, Jiheon Kim1,‡, Doyeon Kim1 and Inseong Jo2,*

1Department of Agricultural Biotechnology, CALS, Seoul National University, Seoul 08826, Republic of Korea
2Division of Therapeutics & Biotechnology, Korea Research Institute of Chemical Technology (KRICT), Deajeon 34114, Republic of Korea

Correspondence to: *
Nayeon Ki’s current address: Ingredient R&D Institute, Ingredient Business Unit, Daesang Corporation, Seoul 03130, Republic of Korea
Jiheon Kim’s current address: R&D Center, Ottogi Corporation, Anyang 14060, Republic of Korea

Received: August 8, 2023; Revised: August 20, 2023; Accepted: September 3, 2023


Pseudomonas aeruginosa is an opportunistic pathogen that often evades eradication by the host immune response, particularly in immunocompromised individuals. Host immune cells produce various antimicrobial oxidants, including H2O2, HOCl, and HOSCN. Recently, a putative peroxiredoxin, RclX, was identified in P. aeruginosa as a highly upregulated gene in response to HOCl and HOSCN. However, the mechanism by which RclX scavenges HOCl and HOSCN stress remains unclear. In this study, we determined the crystal structure of RclX in homohexameric form. The overall structure of RclX closely resembled that of lpg0406, a carboxymuconolactone decarboxylase (CMD) family member from Legionella pneumophila. We found a hydrogen peroxide molecule near the substrate binding pocket, and the conserved CXXC motifs formed disulfide bond bridges in the crystal structure. Our findings provide structural insights into how P. aeruginosa exhibits high resistance to HOCl and HOSCN during host immune responses, with implications for eradicating persistent P. aeruginosa infections.