5f7b

Resting state structure of CuNiR form Alcaligenes faecalis determined at 293 K

spinqualitylabelsall models 5f7b, resolution 1.56Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5f7b is a 3 chain structure with sequence from Alcaligenes faecalis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.56Å Ligands: CU Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function NIR_ALCFA Publication Abstract from PubMed Proton-coupled electron transfer (PCET), a ubiquitous phenomenon in biological systems, plays an essential role in copper nitrite reductase (CuNiR), the key metalloenzyme in microbial denitrification of the global nitrogen cycle. Analyses of the nitrite reduction mechanism in CuNiR with conventional synchrotron radiation crystallography (SRX) have been faced with difficulties, because X-ray photoreduction changes the native structures of metal centers and the enzyme-substrate complex. Using serial femtosecond crystallography (SFX), we determined the intact structures of CuNiR in the resting state and the nitrite complex (NC) state at 2.03- and 1.60-A resolution, respectively. Furthermore, the SRX NC structure representing a transient state in the catalytic cycle was determined at 1.30-A resolution. Comparison between SRX and SFX structures revealed that photoreduction changes the coordination manner of the substrate and that catalytically important His255 can switch hydrogen bond partners between the backbone carbonyl oxygen of nearby Glu279 and the side-chain hydroxyl group of Thr280. These findings, which SRX has failed to uncover, propose a redox-coupled proton switch for PCET. This concept can explain how proton transfer to the substrate is involved in intramolecular electron transfer and why substrate binding accelerates PCET. Our study demonstrates the potential of SFX as a powerful tool to study redox processes in metalloenzymes. Redox-coupled proton transfer mechanism in nitrite reductase revealed by femtosecond crystallography.,Fukuda Y, Tse KM, Nakane T, Nakatsu T, Suzuki M, Sugahara M, Inoue S, Masuda T, Yumoto F, Matsugaki N, Nango E, Tono K, Joti Y, Kameshima T, Song C, Hatsui T, Yabashi M, Nureki O, Murphy ME, Inoue T, Iwata S, Mizohata E Proc Natl Acad Sci U S A. 2016 Feb 29. pii: 201517770. PMID:26929369 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Nitrite reductase 3D structures

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