5gux
Cytochrome c-dependent nitric oxide reductase (cNOR) from Pseudomonas aeruginosa in complex with xenon
Structural highlights
FunctionNORB_PSEAE Component of the anaerobic respiratory chain that transforms nitrate to dinitrogen (denitrification). NorB is the catalytic subunit of the enzyme complex. Shows proton pump activity across the membrane in denitrifying bacterial cells. The mononitrogen reduction is probably coupled to electron transport phosphorylation (By similarity). Publication Abstract from PubMedNitric oxide (NO) plays diverse and significant roles in biological processes despite its cytotoxicity, raising the question of how biological systems control the action of NO to minimize its cytotoxicity in cells. As a great example of such a system, we found a possibility that NO-generating nitrite reductase (NiR) forms a complex with NO-decomposing membrane-integrated NO reductase (NOR) to efficiently capture NO immediately after its production by NiR in anaerobic nitrate respiration called denitrification. The 3.2-A resolution structure of the complex of one NiR functional homodimer and two NOR molecules provides an idea of how these enzymes interact in cells, while the structure may not reflect the one in cells due to the membrane topology. Subsequent all-atom molecular dynamics (MD) simulations of the enzyme complex model in a membrane and structure-guided mutagenesis suggested that a few interenzyme salt bridges and coulombic interactions of NiR with the membrane could stabilize the complex of one NiR homodimer and one NOR molecule and contribute to rapid NO decomposition in cells. The MD trajectories of the NO diffusion in the NiR:NOR complex with the membrane showed that, as a plausible NO transfer mechanism, NO released from NiR rapidly migrates into the membrane, then binds to NOR. These results help us understand the mechanism of the cellular control of the action of cytotoxic NO. Dynamics of nitric oxide controlled by protein complex in bacterial system.,Terasaka E, Yamada K, Wang PH, Hosokawa K, Yamagiwa R, Matsumoto K, Ishii S, Mori T, Yagi K, Sawai H, Arai H, Sugimoto H, Sugita Y, Shiro Y, Tosha T Proc Natl Acad Sci U S A. 2017 Sep 12;114(37):9888-9893. doi:, 10.1073/pnas.1621301114. Epub 2017 Aug 28. PMID:28847930[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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