3gk9
From Proteopedia
Crystal structure of murine Ngb under Xe pressure
Structural highlights
FunctionNGB_MOUSE Involved in oxygen transport in the brain. Hexacoordinate globin, displaying competitive binding of oxygen or the distal His residue to the iron atom. Not capable of penetrating cell membranes. The deoxygenated form exhibits nitrite reductase activity inhibiting cellular respiration via NO-binding to cytochrome c oxidase. Involved in neuroprotection during oxidative stress. May exert its anti-apoptotic activity by acting to reset the trigger level of mitochondrial cytochrome c release necessary to commit the cells to apoptosis.[1] [2] 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 PubMedNeuroglobin (Ngb) is a hexacoordinate globin expressed in the brain of vertebrates. Ferrous Ngb binds dioxygen with high affinity and the O(2) adduct is able to scavenge NO. Convincing in vitro and in vivo data indicate that Ngb is involved in neuroprotection during hypoxia and ischemia. The 3D structure of Ngb reveals the presence of a wide internal cavity connecting its heme active site with the bulk. To explore the role of this "tunnel" in the control of ligand binding, we determined the structure of metNgb and NgbCO equilibrated with Xe or Kr. We show four docking sites for Xe (only two for Kr); two of the four Xe sites are within the large cavity. They are only partially conserved in globins, since the two proximal Xe sites identified in myoglobin (Xe1 and Xe2) are absent in Ngb, as well as in cytoglobin. The Xe docking sites in Ngb map a pathway within the protein matrix, leading to the heme, which becomes more accessible in the ligand-bound species. This may be of significance in connection with the redox chemistry that may be the primary function of this hexacoordinate globin. The structure of neuroglobin at high Xe and Kr pressure reveals partial conservation of globin internal cavities.,Moschetti T, Mueller U, Schulze J, Brunori M, Vallone B Biophys J. 2009 Sep 16;97(6):1700-8. doi: 10.1016/j.bpj.2009.05.059. PMID:19751675[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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