1q1f
Crystal structure of murine neuroglobinCrystal structure of murine neuroglobin
Structural highlights
Function[NGB_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, a recently discovered globin predominantly expressed in neuronal tissue of vertebrates, binds small, gaseous ligands at the sixth coordination position of the heme iron. In the absence of an exogenous ligand, the distal histidine (His64) binds to the heme iron in the ferrous and ferric states. The crystal structure of murine ferric (met) neuroglobin at 1.5 A reveals interesting features relevant to the ligand binding mechanism. Only weak selectivity is observed for the two possible heme orientations, the occupancy ratio being 70:30. Two small internal cavities are present on the heme distal side, which enable the His64(E7) side chain to move out of the way upon exogenous ligand binding. Moreover, a third, huge cavity (volume approximately 290 A3) connecting both sides of the heme, is open towards the exterior and provides a potential passageway for ligands. The CD and EF corners exhibit substantial flexibility, which may assist ligands in entering the protein and accessing the active site. Based on this high-resolution structure, further structure-function studies can be planned to elucidate the role of neuroglobin in physiological responses to hypoxia. The structure of murine neuroglobin: Novel pathways for ligand migration and binding.,Vallone B, Nienhaus K, Brunori M, Nienhaus GU Proteins. 2004 Jul 1;56(1):85-92. PMID:15162488[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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