4u9b

Crystal structure of an H-NOX protein from S. oneidensis in the Fe(II)NO ligation state

spinqualitylabelsall models 4u9b, resolution 1.65Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4u9b is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, HEM, NO, PO4, ZN Related: 4u99, 4u9g, 4u9j, 4u9k, 2kii, 2kil Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Heme-nitric oxide/oxygen (H-NOX) binding domains are a recently discovered family of heme-based gas sensor proteins that are conserved across eukaryotes and bacteria. Nitric oxide (NO) binding to the heme cofactor of H-NOX proteins has been implicated as a regulatory mechanism for processes ranging from vasodilation in mammals to communal behavior in bacteria. A key molecular event during NO-dependent activation of H-NOX proteins is rupture of the heme-histidine bond and formation of a five-coordinate nitrosyl complex. Although extensive biochemical studies have provided insight into the NO activation mechanism, precise molecular-level details have remained elusive. In the present study, high-resolution crystal structures of the H-NOX protein from Shewanella oneidensis in the unligated, intermediate six-coordinate and activated five-coordinate, NO-bound states are reported. From these structures, it is evident that several structural features in the heme pocket of the unligated protein function to maintain the heme distorted from planarity. NO-induced scission of the iron-histidine bond triggers structural rearrangements in the heme pocket that permit the heme to relax toward planarity, yielding the signaling-competent NO-bound conformation. Here, we also provide characterization of a nonheme metal coordination site occupied by zinc in an H-NOX protein. Structural insights into the role of iron-histidine bond cleavage in nitric oxide-induced activation of H-NOX gas sensor proteins.,Herzik MA Jr, Jonnalagadda R, Kuriyan J, Marletta MA Proc Natl Acad Sci U S A. 2014 Sep 24. pii: 201416936. PMID:25253889 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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