1a3g: Difference between revisions
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New page: left|200px<br /><applet load="1a3g" size="450" color="white" frame="true" align="right" spinBox="true" caption="1a3g, resolution 2.5Å" /> '''BRANCHED-CHAIN AMINO ... |
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[[Image:1a3g.gif|left|200px]]<br /><applet load="1a3g" size=" | [[Image:1a3g.gif|left|200px]]<br /><applet load="1a3g" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1a3g, resolution 2.5Å" /> | caption="1a3g, resolution 2.5Å" /> | ||
'''BRANCHED-CHAIN AMINO ACID AMINOTRANSFERASE FROM ESCHERICHIA COLI'''<br /> | '''BRANCHED-CHAIN AMINO ACID AMINOTRANSFERASE FROM ESCHERICHIA COLI'''<br /> | ||
==Overview== | ==Overview== | ||
The X-ray crystallographic structure of the branched-chain amino acid | The X-ray crystallographic structure of the branched-chain amino acid aminotransferase from Escherichia coli was determined by means of isomorphous replacement using the selenomethionyl enzyme as one of the heavy atom derivatives. The enzyme is a homo hexamer with D3 symmetry, and the polypeptide chain of the subunit is folded into two domains (small and large domains). The coenzyme, pyridoxal 5'-phosphate, resides at the domain interface, its re-face facing toward the protein. The active site structure shows that the following sites can recognize branched-chain amino acids and glutamate as substrates: (1) a hydrophobic core formed by Phe36, Tyr164, Tyr31*, and Val109* for a branched-chain; (2) Arg97 for an acidic side chain of glutamate; and (3) Tyr95 and two main chain NH groups of Thr257 and Ala258 for the alpha-carboxylate of substrates. Although the main chain conformation of the active site is homologous to that of D-amino acid aminotransferase, many of the active site residues are different between them. | ||
==About this Structure== | ==About this Structure== | ||
1A3G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with PLP as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Branched-chain-amino-acid_transaminase Branched-chain-amino-acid transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.42 2.6.1.42] Full crystallographic information is available from [http:// | 1A3G is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Branched-chain-amino-acid_transaminase Branched-chain-amino-acid transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.42 2.6.1.42] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1A3G OCA]. | ||
==Reference== | ==Reference== | ||
Three-dimensional structure of Escherichia coli branched-chain amino acid aminotransferase at 2.5 A resolution., Okada K, Hirotsu K, Sato M, Hayashi H, Kagamiyama H, J Biochem | Three-dimensional structure of Escherichia coli branched-chain amino acid aminotransferase at 2.5 A resolution., Okada K, Hirotsu K, Sato M, Hayashi H, Kagamiyama H, J Biochem. 1997 Apr;121(4):637-41. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=9163511 9163511] | ||
[[Category: Branched-chain-amino-acid transaminase]] | [[Category: Branched-chain-amino-acid transaminase]] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
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[[Category: pyridoxal enzyme]] | [[Category: pyridoxal enzyme]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:40:24 2008'' | ||
