4eca: Difference between revisions
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==Overview== | ==Overview== | ||
Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine | Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine to L-aspartate via a threonine-bound acyl-enzyme intermediate. A nearly inactive mutant in which one of the active site threonines, Thr-89, was replaced by valine was constructed, expressed, and crystallized. Its structure, solved at 2.2 A resolution, shows high overall similarity to the wild-type enzyme, but an aspartyl moiety is covalently bound to Thr-12, resembling a reaction intermediate. Kinetic analysis confirms the deacylation deficiency, which is also explained on a structural basis. The previously identified oxyanion hole is described in more detail. | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Lubkowski, J.]] | [[Category: Lubkowski, J.]] | ||
[[Category: Palm, G | [[Category: Palm, G J.]] | ||
[[Category: Wlodawer, A.]] | [[Category: Wlodawer, A.]] | ||
[[Category: acyl-enzyme intermediate]] | [[Category: acyl-enzyme intermediate]] | ||
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[[Category: threonine amidohydrolase]] | [[Category: threonine amidohydrolase]] | ||
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Revision as of 20:13, 21 February 2008
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ASPARAGINASE FROM E. COLI, MUTANT T89V WITH COVALENTLY BOUND ASPARTATE
OverviewOverview
Escherichia coli asparaginase II catalyzes the hydrolysis of L-asparagine to L-aspartate via a threonine-bound acyl-enzyme intermediate. A nearly inactive mutant in which one of the active site threonines, Thr-89, was replaced by valine was constructed, expressed, and crystallized. Its structure, solved at 2.2 A resolution, shows high overall similarity to the wild-type enzyme, but an aspartyl moiety is covalently bound to Thr-12, resembling a reaction intermediate. Kinetic analysis confirms the deacylation deficiency, which is also explained on a structural basis. The previously identified oxyanion hole is described in more detail.
About this StructureAbout this Structure
4ECA is a Single protein structure of sequence from Escherichia coli. Active as Asparaginase, with EC number 3.5.1.1 Known structural/functional Sites: , , and . Full crystallographic information is available from OCA.
ReferenceReference
A covalently bound catalytic intermediate in Escherichia coli asparaginase: crystal structure of a Thr-89-Val mutant., Palm GJ, Lubkowski J, Derst C, Schleper S, Rohm KH, Wlodawer A, FEBS Lett. 1996 Jul 22;390(2):211-6. PMID:8706862
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