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From Proteopedia
Crystal structure of the heterodimeric nitrate reductase from Rhodobacter sphaeroides
Structural highlights
FunctionNAPA_CERS4 Catalytic subunit of the periplasmic nitrate reductase complex NapAB. Receives electrons from NapB and catalyzes the reduction of nitrate to nitrite.[HAMAP-Rule:MF_01630][1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe structure of the respiratory nitrate reductase (NapAB) from Rhodobacter sphaeroides, the periplasmic heterodimeric enzyme responsible for the first step in the denitrification process, has been determined at a resolution of 3.2 A. The di-heme electron transfer small subunit NapB binds to the large subunit with heme II in close proximity to the [4Fe-4S] cluster of NapA. A total of 57 residues at the N- and C-terminal extremities of NapB adopt an extended conformation, embracing the NapA subunit and largely contributing to the total area of 5,900 A(2) buried in the complex. Complex formation was studied further by measuring the variation of the redox potentials of all the cofactors upon binding. The marked effects observed are interpreted in light of the three-dimensional structure and depict a plasticity that contributes to an efficient electron transfer in the complex from the heme I of NapB to the molybdenum catalytic site of NapA. Structural and redox plasticity in the heterodimeric periplasmic nitrate reductase.,Arnoux P, Sabaty M, Alric J, Frangioni B, Guigliarelli B, Adriano JM, Pignol D Nat Struct Biol. 2003 Nov;10(11):928-34. Epub 2003 Oct 5. PMID:14528294[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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