1b5p: Difference between revisions
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New page: left|200px<br /><applet load="1b5p" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b5p, resolution 1.8Å" /> '''THERMUS THERMOPHILUS ... |
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[[Image:1b5p.gif|left|200px]]<br /><applet load="1b5p" size=" | [[Image:1b5p.gif|left|200px]]<br /><applet load="1b5p" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1b5p, resolution 1.8Å" /> | caption="1b5p, resolution 1.8Å" /> | ||
'''THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE DOUBLE MUTANT 1'''<br /> | '''THERMUS THERMOPHILUS ASPARTATE AMINOTRANSFERASE DOUBLE 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== | ||
1B5P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with PO4 and PLP 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:// | 1B5P is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=PLP:'>PLP</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=1B5P 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 thermophilus]] | [[Category: Thermus thermophilus]] | ||
[[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.]] | ||
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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 11:51:45 2008'' | ||
