1q4t
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(New page: 200px<br /><applet load="1q4t" size="450" color="white" frame="true" align="right" spinBox="true" caption="1q4t, resolution 1.60Å" /> '''crystal structure of...)
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Revision as of 01:25, 25 November 2007
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crystal structure of 4-hydroxybenzoyl CoA thioesterase from Arthrobacter sp. strain SU complexed with 4-hydroxyphenyl CoA
Overview
The 4-chlorobenzoyl-CoA dehalogenation pathway in certain Arthrobacter and, Pseudomonas bacterial species contains three enzymes: a ligase, a, dehalogenase, and a thioesterase. Here we describe the high resolution, x-ray crystallographic structure of the 4-hydroxybenzoyl-CoA thioesterase, from Arthrobacter sp. strain SU. The tetrameric enzyme is a dimer of, dimers with each subunit adopting the so-called "hot dog fold" composed of, six strands of anti-parallel beta-sheet flanked on one side by a rather, long alpha-helix. The dimers come together to form the tetramer with their, alpha-helices facing outwards. This quaternary structure is in sharp, contrast to that previously observed for the 4-hydroxybenzoyl-CoA, thioesterase from Pseudomonas species strain CBS-3, whereby the dimers, forming the tetramer pack with their alpha-helices projecting toward the, interfacial region. In the Arthrobacter thioesterase, each of the four, active sites is formed by three of the subunits of the tetramer. On the, basis of both structural and kinetic data, it appears that Glu73 is the, active site base in the Arthrobacter thioesterase. Remarkably, this, residue is located on the opposite side of the substrate-binding pocket, compared with that observed for the Pseudomonas enzyme. Although these two, bacterial thioesterases demonstrate equivalent catalytic efficiencies, substrate specificities, and metabolic functions, their quaternary, structures, CoA-binding sites, and catalytic platforms are decidedly, different.
About this Structure
1Q4T is a Single protein structure of sequence from Arthrobacter sp. with CL, 4CO and EDO as ligands. Active as 4-hydroxybenzoyl-CoA thioesterase, with EC number 3.1.2.23 Full crystallographic information is available from OCA.
Reference
The structure of 4-hydroxybenzoyl-CoA thioesterase from arthrobacter sp. strain SU., Thoden JB, Zhuang Z, Dunaway-Mariano D, Holden HM, J Biol Chem. 2003 Oct 31;278(44):43709-16. Epub 2003 Aug 7. PMID:12907670
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