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Structural Insights into HypB, a GTP-binding Protein That Regulates Metal Binding.

Authors :
Gasper, Raphael
Scrima, Andrea
Wittinghofer, Alfred
Source :
Journal of Biological Chemistry. 9/15/2006, Vol. 281 Issue 37, p27492-27502. 11p. 3 Diagrams, 2 Charts, 3 Graphs.
Publication Year :
2006

Abstract

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 Met hanocaldococcus 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 com- mon 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 ion-binding 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. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219258
Volume :
281
Issue :
37
Database :
Academic Search Index
Journal :
Journal of Biological Chemistry
Publication Type :
Academic Journal
Accession number :
22576449
Full Text :
https://doi.org/10.1074/jbc.M600809200