1czc
From Proteopedia
(New page: 200px<br /><applet load="1czc" size="450" color="white" frame="true" align="right" spinBox="true" caption="1czc, resolution 2.50Å" /> '''ASPARTATE AMINOTRANS...) |
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| - | [[Image:1czc.jpg|left|200px]]<br /><applet load="1czc" size=" | + | [[Image:1czc.jpg|left|200px]]<br /><applet load="1czc" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1czc, resolution 2.50Å" /> | caption="1czc, resolution 2.50Å" /> | ||
'''ASPARTATE AMINOTRANSFERASE MUTANT ATB17/139S/142N WITH GLUTARIC ACID'''<br /> | '''ASPARTATE AMINOTRANSFERASE MUTANT ATB17/139S/142N WITH GLUTARIC ACID'''<br /> | ||
==Overview== | ==Overview== | ||
| - | A mutant Escherichia coil aspartate aminotransferase with 17 amino acid | + | A mutant Escherichia coil aspartate aminotransferase with 17 amino acid substitutions (ATB17), previously created by directed evolution, shows increased activity for beta-branched amino acids and decreased activity for the native substrates, aspartate and glutamate. A new mutant (ATBSN) was generated by changing two of the 17 mutated residues back to the original ones. ATBSN recovered the activities for aspartate and glutamate to the level of the wild-type enzyme while maintaining the enhanced activity of ATB17 for the other amino acid substrates. The absorption spectrum of the bound coenzyme, pyridoxal 5'-phosphate, also returned to the original state. ATBSN shows significantly increased affinity for substrate analogs including succinate and glutarate, analogs of aspartate and glutamate, respectively. Hence, we could cocrystallize ATBSN with succinate or glutarate, and the structures show how the enzyme can bind two kinds of dicarboxylic substrates with different chain lengths. The present results may also provide an insight into the long-standing controversies regarding the mode of binding of glutamate to the wild-type enzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1CZC 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 and GUA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http:// | + | 1CZC 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> and <scene name='pdbligand=GUA:'>GUA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aspartate_transaminase Aspartate transaminase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.6.1.1 2.6.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CZC OCA]. |
==Reference== | ==Reference== | ||
| - | Cocrystallization of a mutant aspartate aminotransferase with a C5-dicarboxylic substrate analog: structural comparison with the enzyme-C4-dicarboxylic analog complex., Oue S, Okamoto A, Yano T, Kagamiyama H, J Biochem | + | Cocrystallization of a mutant aspartate aminotransferase with a C5-dicarboxylic substrate analog: structural comparison with the enzyme-C4-dicarboxylic analog complex., Oue S, Okamoto A, Yano T, Kagamiyama H, J Biochem. 2000 Feb;127(2):337-43. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=10731702 10731702] |
[[Category: Aspartate transaminase]] | [[Category: Aspartate transaminase]] | ||
[[Category: Escherichia coli]] | [[Category: Escherichia coli]] | ||
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[[Category: substrate specificity]] | [[Category: substrate specificity]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:11:17 2008'' |
Revision as of 10:11, 21 February 2008
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ASPARTATE AMINOTRANSFERASE MUTANT ATB17/139S/142N WITH GLUTARIC ACID
Overview
A mutant Escherichia coil aspartate aminotransferase with 17 amino acid substitutions (ATB17), previously created by directed evolution, shows increased activity for beta-branched amino acids and decreased activity for the native substrates, aspartate and glutamate. A new mutant (ATBSN) was generated by changing two of the 17 mutated residues back to the original ones. ATBSN recovered the activities for aspartate and glutamate to the level of the wild-type enzyme while maintaining the enhanced activity of ATB17 for the other amino acid substrates. The absorption spectrum of the bound coenzyme, pyridoxal 5'-phosphate, also returned to the original state. ATBSN shows significantly increased affinity for substrate analogs including succinate and glutarate, analogs of aspartate and glutamate, respectively. Hence, we could cocrystallize ATBSN with succinate or glutarate, and the structures show how the enzyme can bind two kinds of dicarboxylic substrates with different chain lengths. The present results may also provide an insight into the long-standing controversies regarding the mode of binding of glutamate to the wild-type enzyme.
About this Structure
1CZC is a Single protein structure of sequence from Escherichia coli with and as ligands. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
Reference
Cocrystallization of a mutant aspartate aminotransferase with a C5-dicarboxylic substrate analog: structural comparison with the enzyme-C4-dicarboxylic analog complex., Oue S, Okamoto A, Yano T, Kagamiyama H, J Biochem. 2000 Feb;127(2):337-43. PMID:10731702
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