2xwp

ANAEROBIC COBALT CHELATASE (CBIK) FROM SALMONELLA TYPHIMURIUM IN COMPLEX WITH METALATED TETRAPYRROLE

spinqualitylabelsall models 2xwp, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xwp is a 1 chain structure with sequence from Salmonella enterica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, SIR Related: 1qgo, 2xws, 2xwq Activity: Sirohydrochlorin cobaltochelatase, with EC number 4.99.1.3 Resources: FirstGlance, OCA, RCSB, PDBsum Function [CBIK_SALTY] Catalyzes the insertion of Co(2+) into sirohydrochlorin as part of the anaerobic pathway to cobalamin biosynthesis. Publication Abstract from PubMed The class II chelatases associated with heme, siroheme, and cobalamin biosynthesis are structurally related enzymes that insert a specific metal ion (Fe(2+) or Co(2+)) into the center of a modified tetrapyrrole (protoporphyrin or sirohydrochlorin). The structures of two related class II enzymes, CbiX(S) from Archaeoglobus fulgidus and CbiK from Salmonella enterica, that are responsible for the insertion of cobalt along the cobalamin biosynthesis pathway are presented in complex with their metallated product. A further structure of a CbiK from Desulfovibrio vulgaris Hildenborough reveals how cobalt is bound at the active site. The crystal structures show that the binding of sirohydrochlorin is distinctly different to porphyrin binding in the protoporphyrin ferrochelatases and provide a molecular overview of the mechanism of chelation. The structures also give insights into the evolution of chelatase form and function. Finally, the structure of a periplasmic form of Desulfovibrio vulgaris Hildenborough CbiK reveals a novel tetrameric arrangement of its subunits that are stabilized by the presence of a heme b cofactor. Whereas retaining colbaltochelatase activity, this protein has acquired a central cavity with the potential to chaperone or transport metals across the periplasmic space, thereby evolving a new use for an ancient protein subunit. Evolution in a family of chelatases facilitated by the introduction of active site asymmetry and protein oligomerization.,Romao CV, Ladakis D, Lobo SA, Carrondo MA, Brindley AA, Deery E, Matias PM, Pickersgill RW, Saraiva LM, Warren MJ Proc Natl Acad Sci U S A. 2010 Dec 20. PMID:21173279 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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