5mdk | pdb_00005mdk

Crystal structure of an O2-tolerant [NiFe]-hydrogenase from Ralstonia eutropha in its as-isolated form (oxidized state - state 3)

spinqualitylabelsall models 5mdk, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5mdk is a 2 chain structure with sequence from Cupriavidus necator H16. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.5Å Ligands: CL, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MBHL_CUPNH This enzyme recycles the H(2) produced by nitrogenase to increase the production of ATP and to protect nitrogenase against inhibition or damage by O(2) under carbon- or phosphate-limited conditions. Publication Abstract from PubMed [NiFe] hydrogenases catalyze the reversible splitting of H2 into protons and electrons at a deeply buried active site. The catalytic center can be accessed by gas molecules through a hydrophobic tunnel network. While most [NiFe] hydrogenases are inactivated by O2, a small subgroup, including the membrane-bound [NiFe] hydrogenase (MBH) of Ralstonia eutropha, is able to overcome aerobic inactivation by catalytic reduction of O2 to water. This O2 tolerance relies on a special [4Fe3S] cluster that is capable of releasing two electrons upon O2 attack. Here, the O2 accessibility of the MBH gas tunnel network has been probed experimentally using a "soak-and-freeze" derivatization method, accompanied by protein X-ray crystallography and computational studies. This combined approach revealed several sites of O2 molecules within a hydrophobic tunnel network leading, via two tunnel entrances, to the catalytic center of MBH. The corresponding site occupancies were related to the O2 concentrations used for MBH crystal derivatization. The examination of the O2-derivatized data furthermore uncovered two unexpected structural alterations at the [4Fe3S] cluster, which might be related to the O2 tolerance of the enzyme. Tracking the route of molecular oxygen in O2-tolerant membrane-bound [NiFe] hydrogenase.,Kalms J, Schmidt A, Frielingsdorf S, Utesch T, Gotthard G, von Stetten D, van der Linden P, Royant A, Mroginski MA, Carpentier P, Lenz O, Scheerer P Proc Natl Acad Sci U S A. 2018 Mar 6;115(10):E2229-E2237. doi:, 10.1073/pnas.1712267115. Epub 2018 Feb 20. PMID:29463722 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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