1vcm
From Proteopedia
Crystal Structure of T.th. HB8 CTP synthetase
Overview
CTP synthetase (CTPs) catalyzes the last step in CTP biosynthesis, in which ammonia generated at the glutaminase domain reacts with the ATP-phosphorylated UTP at the synthetase domain to give CTP. Glutamine hydrolysis is active in the presence of ATP and UTP and is stimulated by the addition of GTP. We report the crystal structures of Thermus thermophilus HB8 CTPs alone, CTPs with 3SO4(2-), and CTPs with glutamine. The enzyme is folded into a homotetramer with a cross-shaped structure. Based on the binding mode of sulfate anions to the synthetase site, ATP and UTP are computer modeled into CTPs with a geometry favorable for the reaction. Glutamine bound to the glutaminase domain is situated next to the triad of Glu-His-Cys as a catalyst and a water molecule. Structural information provides an insight into the conformational changes associated with the binding of ATP and UTP and the formation of the GTP binding site.
About this Structure
Full crystallographic information is available from OCA.
Reference
Crystal structures of CTP synthetase reveal ATP, UTP, and glutamine binding sites., Goto M, Omi R, Nakagawa N, Miyahara I, Hirotsu K, Structure. 2004 Aug;12(8):1413-23. PMID:15296735 Page seeded by OCA on Sat May 3 12:22:37 2008
