5aun

Crystal structure of the HypAB-Ni complex

spinqualitylabelsall models 5aun, resolution 1.63Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5aun is a 2 chain structure with sequence from Thermococcus kodakarensis KOD1. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ADP, CL, GOL, MG, NI, URE, ZN Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function HYPA_THEKO Probably plays a role in a hydrogenase nickel cofactor insertion step (By similarity). Publication Abstract from PubMed The Ni atom at the catalytic center of [NiFe] hydrogenases is incorporated by a Ni-metallochaperone, HypA, and a GTPase/ATPase, HypB. We report the crystal structures of the transient complex formed between HypA and ATPase-type HypB (HypBAT) with Ni ions. Transient association between HypA and HypBAT is controlled by the ATP hydrolysis cycle of HypBAT, which is accelerated by HypA. Only the ATP-bound form of HypBAT can interact with HypA and induces drastic conformational changes of HypA. Consequently, upon complex formation, a conserved His residue of HypA comes close to the N-terminal conserved motif of HypA and forms a Ni-binding site, to which a Ni ion is bound with a nearly square-planar geometry. The Ni binding site in the HypABAT complex has a nanomolar affinity (Kd = 7 nM), which is in contrast to the micromolar affinity (Kd = 4 microM) observed with the isolated HypA. The ATP hydrolysis and Ni binding cause conformational changes of HypBAT, affecting its association with HypA. These findings indicate that HypA and HypBAT constitute an ATP-dependent Ni acquisition cycle for [NiFe]-hydrogenase maturation, wherein HypBAT functions as a metallochaperone enhancer and considerably increases the Ni-binding affinity of HypA. Structural basis of a Ni acquisition cycle for [NiFe] hydrogenase by Ni-metallochaperone HypA and its enhancer.,Watanabe S, Kawashima T, Nishitani Y, Kanai T, Wada T, Inaba K, Atomi H, Imanaka T, Miki K Proc Natl Acad Sci U S A. 2015 Jun 8. pii: 201503102. PMID:26056269 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also HypA%2C HypB%2C HypC%2C HypD%2C HypE and HypF 3D structures

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