2j8r
From Proteopedia
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STRUCTURE OF P. AERUGINOSA ACETYLTRANSFERASE PA4866 SOLVED IN COMPLEX WITH L-METHIONINE SULFOXIMINE
Overview
The gene PA4866 from Pseudomonas aeruginosa is documented in the, Pseudomonas genome database as encoding a 172 amino acid hypothetical, acetyltransferase. We and others have described the 3D structure of this, protein (termed pita) [Davies et al. (2005) Proteins: Struct., Funct., Bioinf. 61, 677-679; Nocek et al., unpublished results], and structures, have also been reported for homologues from Agrobacterium tumefaciens, (Rajashankar et al., unpublished results) and Bacillus subtilis [Badger et, al. (2005) Proteins: Struct., Funct., Bioinf. 60, 787-796]. Pita, homologues are found in a large number of bacterial genomes, and while the, majority of these have been assigned putative phosphinothricin, acetyltransferase activity, their true function is unknown. In this paper, we report that pita has no activity toward phosphinothricin. Instead, we, demonstrate that pita acts as an acetyltransferase using the glutamate, analogues l-methionine sulfoximine and l-methionine sulfone as substrates, with Km(app) values of 1.3 +/- 0.21 and 1.3 +/- 0.13 mM and kcat(app), values of 505 +/- 43 and 610 +/- 23 s-1 for l-methionine sulfoximine and, l-methionine sulfone, respectively. A high-resolution (1.55 A) crystal, structure of pita in complex with one of these substrates (l-methionine, sulfoximine) has been solved, revealing the mode of its interaction with, the enzyme. Comparison with the apoenzyme structure has also revealed how, certain active site residues undergo a conformational change upon, substrate binding. To investigate the role of pita in P. aeruginosa, a, mutant strain, Depp4, in which pita was inactivated through an in-frame, deletion, was constructed by allelic exchange. Growth of strain Depp4 in, the absence of glutamine was inhibited by l-methionine sulfoximine, suggesting a role for pita in protecting glutamine synthetase from, inhibition.
About this Structure
2J8R is a Single protein structure of sequence from Pseudomonas aeruginosa with , and as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
l-Methionine sulfoximine, but not phosphinothricin, is a substrate for an acetyltransferase (gene PA4866) from Pseudomonas aeruginosa: structural and functional studies., Davies AM, Tata R, Beavil RL, Sutton BJ, Brown PR, Biochemistry. 2007 Feb 20;46(7):1829-39. Epub 2007 Jan 25. PMID:17253769
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