1u80
From Proteopedia
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Phosphopantothenoylcysteine synthetase from E. coli, CMP complex
Overview
Phosphopantothenoylcysteine (PPC) synthetase forms a peptide bond between 4'-phosphopantothenate and cysteine in coenzyme A biosynthesis. PPC synthetases fall into two classes: eukaryotic, ATP-dependent and eubacterial, CTP-dependent enzymes. We describe the first crystal structure of E. coli PPC synthetase as a prototype of bacterial, CTP-dependent PPC synthetases. Structures of the apo-form and the synthetase complexed with CTP, the activated acyl-intermediate, 4'-phosphopantothenoyl-CMP, and with the reaction product CMP provide snapshots along the reaction pathway and detailed insight into substrate binding and the reaction mechanism of peptide bond formation. Binding of the phosphopantothenate moiety of the acyl-intermediate in a cleft at the C-terminal end of the central beta sheet of the dinucleotide binding fold is accomplished by an otherwise flexible flap. A second disordered loop may control access of cysteine to the active site. The conservation of functionalities involved in substrate binding and catalysis provides insight into similarities and differences of prokaryotic and eukaryotic PPC synthetases.
About this Structure
1U80 is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Phosphopantothenate--cysteine ligase, with EC number 6.3.2.5 Full crystallographic information is available from OCA.
Reference
Structural basis of CTP-dependent peptide bond formation in coenzyme A biosynthesis catalyzed by Escherichia coli PPC synthetase., Stanitzek S, Augustin MA, Huber R, Kupke T, Steinbacher S, Structure. 2004 Nov;12(11):1977-88. PMID:15530362
Page seeded by OCA on Thu Feb 21 15:21:35 2008
