2hf9
From Proteopedia
Crystal structure of HypB from Methanocaldococcus jannaschii in the triphosphate form
Overview
HypB is a prokaryotic metal-binding guanine nucleotide-binding protein that is essential for nickel incorporation into hydrogenases. Here we solved the x-ray structure of HypB from Methanocaldococcus jannaschii. It shows that the G-domain has a different topology than the Ras-like proteins and belongs to the SIMIBI (after Signal Recognition Particle, MinD and BioD) class of NTP-binding proteins. We show that HypB undergoes nucleotide-dependent dimerization, which is apparently a common feature of SIMIBI class G-proteins. The nucleotides are located in the dimer interface and are contacted by both subunits. The active site features residues from both subunits arguing that hydrolysis also requires dimerization. Two metal-binding sites are found, one of which is dependent on the state of bound nucleotide. A totally conserved ENV/IGNLV/ICP motif in switch II relays the nucleotide binding with the metal ionbinding site. The homology with NifH, the Fe protein subunit of nitrogenase, suggests a mechanistic model for the switch-dependent incorporation of a metal ion into hydrogenases.
About this Structure
2HF9 is a Single protein structure of sequence from Methanocaldococcus jannaschii. Full crystallographic information is available from OCA.
Reference
Structural insights into HypB, a GTP-binding protein that regulates metal binding., Gasper R, Scrima A, Wittinghofer A, J Biol Chem. 2006 Sep 15;281(37):27492-502. Epub 2006 Jun 28. PMID:16807243 Page seeded by OCA on Sun May 4 06:13:24 2008
