6gx4

The molybdenum storage protein: with ATP/Mn2+ and with POM clusters formed under in vitro conditions

spinqualitylabelsall models 6gx4, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6gx4 is a 2 chain structure with sequence from Azotobacter vinelandii DJ. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.9Å Ligands: ATP, FUQ, MN, MOO, PO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function MOSB_AZOVD Intracellular storage of molybdenum. Binds polyoxomolybdates. Can bind at least 90 molybdenum atoms per protein molecule. Publication Abstract from PubMed A continuous FeMo-cofactor supply for nitrogenase maturation is ensured in Azotobacter vinelandii by developing a cage-like molybdenum storage protein (MoSto) capable to store ca. 120 molybdate molecules (MoO4 (2-) ) as discrete polyoxometalate (POM) clusters. To gain mechanistic insight into this process MoSto was characterized by Mo and ATP/ADP content, structural and kinetic analysis. We defined three functionally relevant states specified by the presence of both ATP/ADP and POM clusters (MoStofunct ), of only ATP/ADP (MoStobasal ) and of neither ATP/ADP nor POM clusters (MoStozero ), respectively. POM clusters are only produced when ATP is hydrolyzed to ADP and phosphate. Vmax was ca. 13 mumolphosphate min(-1) mg(-1) and Km for molybdate and ATP/Mg(2+) in the low micromolar range. ATP hydrolysis presumably proceeds at subunit alpha, which is compatible with a highly occupied alpha-ATP/Mg(2+) and a weaker occupied beta-ATP/no Mg(2+) binding site found in the MoStofunct structure. Several findings indicate that POM cluster storage is separated into a rapid ATP-hydrolysis dependent molybdate transport across the protein cage wall and a slow molybdate assembly induced by combined auto-catalytic and protein-driven processes. The cage interior, the location of the POM cluster depot, is locked in all three states and thus not rapidly accessible for molybdate from the outside. Based on Vmax the entire Mo storage process should be completed in less than 10 s but requires, according to the molybdate content analysis, ca. 15 min. Long-time incubation of MoStobasal with non-physiological high molybdate amounts implicates an equilibrium in and outside the cage and POM cluster self-formation without ATP hydrolysis. This article is protected by copyright. All rights reserved. The Molybdenum Storage Protein: A soluble ATP hydrolysis dependent molybdate pump.,Poppe J, Brunle S, Hail R, Wiesemann K, Schneider K, Ermler U FEBS J. 2018 Oct 27. doi: 10.1111/febs.14684. PMID:30367742 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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