1f7l
From Proteopedia
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HOLO-(ACYL CARRIER PROTEIN) SYNTHASE IN COMPLEX WITH COENZYME A AT 1.5A
Overview
BACKGROUND: Holo-(acyl carrier protein) synthase (AcpS), a member of the, phosphopantetheinyl transferase superfamily, plays a crucial role in the, functional activation of acyl carrier protein (ACP) in the fatty acid, biosynthesis pathway. AcpS catalyzes the attachment of the, 4'-phosphopantetheinyl moiety of coenzyme A (CoA) to the sidechain of a, conserved serine residue on apo-ACP. RESULTS: We describe here the first, crystal structure of a type II ACP from Bacillus subtilis in complex with, its activator AcpS at 2.3 A. We also have determined the structures of, AcpS alone (at 1.8 A) and AcpS in complex with CoA (at 1.5 A). These, structures reveal that AcpS exists as a trimer. A catalytic center is, located at each of the solvent-exposed interfaces between AcpS molecules., Site-directed mutagenesis studies confirm the importance of trimer, formation in AcpS activity. CONCLUSIONS: The active site in AcpS is only, formed when two AcpS molecules dimerize. The addition of a third molecule, allows for the formation of two additional active sites and also permits a, large hydrophobic surface from each molecule of AcpS to be buried in the, trimer. The mutations Ile5-->Arg, Gln113-->Glu and Gln113-->Arg show that, AcpS is inactive when unable to form a trimer. The co-crystal structures, of AcpS-CoA and AcpS-ACP allow us to propose a catalytic mechanism for, this class of 4'-phosphopantetheinyl transferases.
About this Structure
1F7L is a Single protein structure of sequence from Bacillus subtilis with CA, CL and COA as ligands. Active as [acyl-carrier-protein_synthase Holo-[acyl-carrier-protein] synthase], with EC number 2.7.8.7 Full crystallographic information is available from OCA.
Reference
Crystal structures of substrate binding to Bacillus subtilis holo-(acyl carrier protein) synthase reveal a novel trimeric arrangement of molecules resulting in three active sites., Parris KD, Lin L, Tam A, Mathew R, Hixon J, Stahl M, Fritz CC, Seehra J, Somers WS, Structure. 2000 Aug 15;8(8):883-95. PMID:10997907[[Category: Holo-[acyl-carrier-protein] synthase]]
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