5bj3: Difference between revisions
New page: left|200px<br /><applet load="5bj3" size="450" color="white" frame="true" align="right" spinBox="true" caption="5bj3, resolution 2.2Å" /> '''THERMUS THERMOPHILUS ... |
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[[Image:5bj3.gif|left|200px]]<br /><applet load="5bj3" size=" | [[Image:5bj3.gif|left|200px]]<br /><applet load="5bj3" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="5bj3, resolution 2.2Å" /> | caption="5bj3, resolution 2.2Å" /> | ||
'''THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE TETRA MUTANT 1'''<br /> | '''THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE TETRA MUTANT 1'''<br /> | ||
==Overview== | ==Overview== | ||
Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for | Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for an acidic substrate. However, stepwise introduction of mutations in the active-site residues finally changed its substrate specificity to that of a dual-substrate enzyme. The final mutant, [S15D, T17V, K109S, S292R] ttAspAT, is active toward both acidic and hydrophobic substrates. During the course of stepwise mutation, the activities toward acidic and hydrophobic substrates changed independently. The introduction of a mobile Arg292* residue into ttAspAT was the key step in the change to a "dual-substrate" enzyme. The substrate recognition mechanism of this thermostable "dual-substrate" enzyme was confirmed by X-ray crystallography. This work together with previous studies on various enzymes suggest that this unique "dual-substrate recognition" mechanism is a feature of not only aminotransferases but also other enzymes. | ||
==About this Structure== | ==About this Structure== | ||
5BJ3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus] with PLP as [http://en.wikipedia.org/wiki/ligand ligand]. 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:// | 5BJ3 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_aquaticus Thermus aquaticus] with <scene name='pdbligand=PLP:'>PLP</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. 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=5BJ3 OCA]. | ||
==Reference== | ==Reference== | ||
Substrate recognition mechanism of thermophilic dual-substrate enzyme., Ura H, Nakai T, Kawaguchi SI, Miyahara I, Hirotsu K, Kuramitsu S, J Biochem | Substrate recognition mechanism of thermophilic dual-substrate enzyme., Ura H, Nakai T, Kawaguchi SI, Miyahara I, Hirotsu K, Kuramitsu S, J Biochem. 2001 Jul;130(1):89-98. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=11432784 11432784] | ||
[[Category: Aspartate transaminase]] | [[Category: Aspartate transaminase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Thermus aquaticus]] | [[Category: Thermus aquaticus]] | ||
[[Category: Hirotsu, K.]] | [[Category: Hirotsu, K.]] | ||
[[Category: Kawaguchi, S | [[Category: Kawaguchi, S I.]] | ||
[[Category: Kuramitsu, S.]] | [[Category: Kuramitsu, S.]] | ||
[[Category: Miyahara, I.]] | [[Category: Miyahara, I.]] | ||
| Line 24: | Line 24: | ||
[[Category: pyridoxal enzyme]] | [[Category: pyridoxal enzyme]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:14:52 2008'' | ||
Revision as of 20:14, 21 February 2008
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THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE TETRA MUTANT 1
OverviewOverview
Aspartate aminotransferase from an extremely thermophilic bacterium, Thermus thermophilus HB8 (ttAspAT), has been believed to be specific for an acidic substrate. However, stepwise introduction of mutations in the active-site residues finally changed its substrate specificity to that of a dual-substrate enzyme. The final mutant, [S15D, T17V, K109S, S292R] ttAspAT, is active toward both acidic and hydrophobic substrates. During the course of stepwise mutation, the activities toward acidic and hydrophobic substrates changed independently. The introduction of a mobile Arg292* residue into ttAspAT was the key step in the change to a "dual-substrate" enzyme. The substrate recognition mechanism of this thermostable "dual-substrate" enzyme was confirmed by X-ray crystallography. This work together with previous studies on various enzymes suggest that this unique "dual-substrate recognition" mechanism is a feature of not only aminotransferases but also other enzymes.
About this StructureAbout this Structure
5BJ3 is a Single protein structure of sequence from Thermus aquaticus with as ligand. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Substrate recognition mechanism of thermophilic dual-substrate enzyme., Ura H, Nakai T, Kawaguchi SI, Miyahara I, Hirotsu K, Kuramitsu S, J Biochem. 2001 Jul;130(1):89-98. PMID:11432784
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