1t5h
From Proteopedia
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| , resolution 2.002Å | |||||||
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| Ligands: | |||||||
| Activity: | 4-chlorobenzoate--CoA ligase, with EC number 6.2.1.33 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
4-Chlorobenzoyl-CoA Ligase/Synthetase unliganded, selenomethionine
Overview
4-Chlorobenzoate:CoA ligase (CBAL) is a member of a family of adenylate-forming enzymes that catalyze two-step adenylation and thioester-forming reactions. In previous studies, we have provided structural evidence that members of this enzyme family (exemplified by acetyl-CoA synthetase) use a large domain rotation to catalyze the respective partial reactions [A. M. Gulick, V. J. Starai, A. R. Horswill, K. M. Homick, and J. C. Escalante-Semerena, (2003) Biochemistry 42, 2866-2873]. CBAL catalyzes the synthesis of 4-chlorobenzoyl-CoA, the first step in the 4-chlorobenzoate degredation pathway in PCB-degrading bacteria. We have solved the 2.0 A crystal structure of the CBAL enzyme from Alcaligenes sp. AL3007 using multiwavelength anomalous dispersion. The results demonstrate that in the absence of any ligands, or bound to the aryl substrate 4-chlorobenzoate, the enzyme adopts the conformation poised for catalysis of the adenylate-forming half-reaction. We hypothesize that coenzyme A binding is required for stabilization of the alternate conformation, which catalyzes the 4-CBA-CoA thioester-forming reaction. We have also determined the structure of the enzyme bound to the aryl substrate 4-chlorobenzoate. The aryl binding pocket is composed of Phe184, His207, Val208, Val209, Phe249, Ala280, Ile303, Gly305, Met310, and Asn311. The structure of the 4-chlorobenzoate binding site is discussed in the context of the binding sites of other family members to gain insight into substrate specificity and evolution of new function.
About this Structure
1T5H is a Single protein structure of sequence from Alcaligenes sp. al3007. Full crystallographic information is available from OCA.
Reference
Crystal structure of 4-chlorobenzoate:CoA ligase/synthetase in the unliganded and aryl substrate-bound states., Gulick AM, Lu X, Dunaway-Mariano D, Biochemistry. 2004 Jul 13;43(27):8670-9. PMID:15236575
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