2z9v
From Proteopedia
| Line 11: | Line 11: | ||
'''Crystal structure of pyridoxamine-pyruvate aminotransferase complexed with pyridoxamine''' | '''Crystal structure of pyridoxamine-pyruvate aminotransferase complexed with pyridoxamine''' | ||
| + | |||
| + | ==Overview== | ||
| + | Pyridoxamine-pyruvate aminotransferase (PPAT; EC 2.6.1.30) is a pyridoxal 5'-phosphate-independent aminotransferase and catalyzes reversible transamination between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The crystal structure of PPAT from Mesorhizobium loti has been solved in space group P4(3)2(1)2 and was refined to an R factor of 15.6% (R(free) = 20.6%) at 2.0 A resolution. In addition, the structures of PPAT in complexes with pyridoxamine, pyridoxal, and pyridoxyl-L-alanine have been refined to R factors of 15.6, 15.4, and 14.5% (R(free) = 18.6, 18.1, and 18.4%) at 1.7, 1.7, and 2.0 A resolution, respectively. PPAT is a homotetramer and each subunit is composed of a large N-terminal domain, consisting of seven beta-sheets and eight alpha-helices, and a smaller C-terminal domain, consisting of three beta-sheets and four alpha-helices. The substrate pyridoxal is bound through an aldimine linkage to Lys-197 in the active site. The alpha-carboxylate group of the substrate amino/keto acid is hydrogen-bonded to Arg-336 and Arg-345. The structures revealed that the bulky side chain of Glu-68 interfered with the binding of the phosphate moiety of pyridoxal 5'-phosphate and made PPAT specific to pyridoxal. The reaction mechanism of the enzyme is discussed based on the structures and kinetics results. | ||
==About this Structure== | ==About this Structure== | ||
2Z9V is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Mesorhizobium_loti Mesorhizobium loti]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2Z9V OCA]. | 2Z9V is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Mesorhizobium_loti Mesorhizobium loti]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2Z9V OCA]. | ||
| + | |||
| + | ==Reference== | ||
| + | Crystal structure of pyridoxamine-pyruvate aminotransferase from Mesorhizobium loti MAFF303099., Yoshikane Y, Yokochi N, Yamasaki M, Mizutani K, Ohnishi K, Mikami B, Hayashi H, Yagi T, J Biol Chem. 2008 Jan 11;283(2):1120-7. Epub 2007 Nov 6. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/17989071 17989071] | ||
[[Category: Mesorhizobium loti]] | [[Category: Mesorhizobium loti]] | ||
[[Category: Pyridoxamine--pyruvate transaminase]] | [[Category: Pyridoxamine--pyruvate transaminase]] | ||
| Line 28: | Line 34: | ||
[[Category: Pyridoxamine]] | [[Category: Pyridoxamine]] | ||
[[Category: Pyruvate]] | [[Category: Pyruvate]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jun 4 10:00:39 2008'' |
Revision as of 07:00, 4 June 2008
Crystal structure of pyridoxamine-pyruvate aminotransferase complexed with pyridoxamine
Overview
Pyridoxamine-pyruvate aminotransferase (PPAT; EC 2.6.1.30) is a pyridoxal 5'-phosphate-independent aminotransferase and catalyzes reversible transamination between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The crystal structure of PPAT from Mesorhizobium loti has been solved in space group P4(3)2(1)2 and was refined to an R factor of 15.6% (R(free) = 20.6%) at 2.0 A resolution. In addition, the structures of PPAT in complexes with pyridoxamine, pyridoxal, and pyridoxyl-L-alanine have been refined to R factors of 15.6, 15.4, and 14.5% (R(free) = 18.6, 18.1, and 18.4%) at 1.7, 1.7, and 2.0 A resolution, respectively. PPAT is a homotetramer and each subunit is composed of a large N-terminal domain, consisting of seven beta-sheets and eight alpha-helices, and a smaller C-terminal domain, consisting of three beta-sheets and four alpha-helices. The substrate pyridoxal is bound through an aldimine linkage to Lys-197 in the active site. The alpha-carboxylate group of the substrate amino/keto acid is hydrogen-bonded to Arg-336 and Arg-345. The structures revealed that the bulky side chain of Glu-68 interfered with the binding of the phosphate moiety of pyridoxal 5'-phosphate and made PPAT specific to pyridoxal. The reaction mechanism of the enzyme is discussed based on the structures and kinetics results.
About this Structure
2Z9V is a Single protein structure of sequence from Mesorhizobium loti. Full crystallographic information is available from OCA.
Reference
Crystal structure of pyridoxamine-pyruvate aminotransferase from Mesorhizobium loti MAFF303099., Yoshikane Y, Yokochi N, Yamasaki M, Mizutani K, Ohnishi K, Mikami B, Hayashi H, Yagi T, J Biol Chem. 2008 Jan 11;283(2):1120-7. Epub 2007 Nov 6. PMID:17989071 Page seeded by OCA on Wed Jun 4 10:00:39 2008
