1qdb
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CYTOCHROME C NITRITE REDUCTASE
OverviewOverview
The enzyme cytochrome c nitrite reductase catalyses the six-electron reduction of nitrite to ammonia as one of the key steps in the biological nitrogen cycle, where it participates in the anaerobic energy metabolism of dissimilatory nitrate ammonification. Here we report on the crystal structure of this enzyme from the microorganism Sulfurospirillum deleyianum, which we solved by multiwavelength anomalous dispersion methods. We propose a reaction scheme for the transformation of nitrite based on structural and spectroscopic information. Cytochrome c nitrite reductase is a functional dimer, with 10 close-packed haem groups of type c and an unusual lysine-coordinated high-spin haem at the active site. By comparing the haem arrangement of this nitrite reductase with that of other multihaem cytochromes, we have been able to identify a family of proteins in which the orientation of haem groups is conserved whereas structure and function are not.
About this StructureAbout this Structure
1QDB is a Single protein structure of sequence from Sulfurospirillum deleyianum with , and as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Structure of cytochrome c nitrite reductase., Einsle O, Messerschmidt A, Stach P, Bourenkov GP, Bartunik HD, Huber R, Kroneck PM, Nature. 1999 Jul 29;400(6743):476-80. PMID:10440380
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