6KYY

Cu(II) complex of HOCl-induced flavoprotein disulfide reductase RclA from Escherichia coli

Summary for 6KYY

• Entry DOI: 10.2210/pdb6kyy/pdb
• Descriptor: Pyridine nucleotide-disulphide oxidoreductase dimerisation region, FLAVIN-ADENINE DINUCLEOTIDE, COPPER (II) ION, ... (4 entities in total)
• Functional Keywords: flavoprotein, hypochlorous acid, reductase, cysteine disulfide, oxidoreductase, copper, cupric ion
• Biological source: Escherichia coli BL21(DE3)
• Total number of polymer chains: 4
• Total formula weight: 201393.86

Authors

Baek, Y.,Ha, N.-C. (deposition date: 2019-09-20, release date: 2020-02-05, Last modification date: 2023-11-22)

Primary citation

Baek, Y.,Kim, J.,Ahn, J.,Jo, I.,Hong, S.,Ryu, S.,Ha, N.C.
Structure and function of the hypochlorous acid-induced flavoprotein RclA fromEscherichia coli.
J.Biol.Chem., 295:3202-3212, 2020

PubMed Abstract: In response to microbial invasion, the animal immune system generates hypochlorous acid (HOCl) that kills microorganisms in the oxidative burst. HOCl toxicity is amplified in the phagosome through import of the copper cation (Cu). In and , the transcriptional regulator RclR senses HOCl stress and induces expression of the RclA, -B, and -C proteins involved in bacterial defenses against oxidative stress. However, the structures and biochemical roles of the Rcl proteins remain to be elucidated. In this study, we first examined the role of the flavoprotein disulfide reductase (FDR) RclA in the survival of in macrophage phagosomes, finding that RclA promotes survival in macrophage vacuoles containing sublethal HOCl levels. To clarify the molecular mechanism, we determined the crystal structure of RclA from at 2.9 Å resolution. This analysis revealed that the structure of homodimeric RclA is similar to those of typical FDRs, exhibiting two conserved cysteine residues near the flavin ring of the cofactor flavin adenine dinucleotide (FAD). Of note, we observed that Cu accelerated RclA-mediated oxidation of NADH, leading to a lowering of oxygen levels Compared with the RclA WT enzyme, substitution of the conserved cysteine residues lowered the specificity to Cu or substantially increased the production of superoxide anion in the absence of Cu We conclude that RclA-mediated lowering of oxygen levels could contribute to the inhibition of oxidative bursts in phagosomes. Our study sheds light on the molecular basis for how bacteria can survive HOCl stress in macrophages.

PubMed: 31988242
DOI: 10.1074/jbc.RA119.011530

Experimental method

X-RAY DIFFRACTION (2.8 Å)