2a8m

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(New page: 200px<br /> <applet load="2a8m" size="450" color="white" frame="true" align="right" spinBox="true" caption="2a8m, resolution 2.60&Aring;" /> '''Crystal Structure o...)
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<applet load="2a8m" size="450" color="white" frame="true" align="right" spinBox="true"
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caption="2a8m, resolution 2.60&Aring;" />
caption="2a8m, resolution 2.60&Aring;" />
'''Crystal Structure of Human Taspase1 (T234S mutant)'''<br />
'''Crystal Structure of Human Taspase1 (T234S mutant)'''<br />
==Overview==
==Overview==
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Taspase1 catalyzes the proteolytic processing of the mixed lineage, leukemia (MLL) nuclear protein, which is required for maintaining Hox gene, expression patterns. Chromosomal translocations of the MLL gene are, associated with leukemia in infants. Taspase1, a threonine aspartase, is a, member of the type 2 asparaginase family, but is the only protease in this, family. We report here the crystal structures of human activated Taspase1, and its proenzyme, as well as the characterization of the effects of, mutations in the active site region using a newly developed fluorogenic, assay. The structure of Taspase1 has significant differences from other, asparaginases, especially near the active site. Mutation of the catalytic, nucleophile, Thr234, abolishes autocatalytic processing in cis but does, not completely block proteolysis in trans. The structure unexpectedly, showed the binding of a chloride ion in the active site, and our kinetic, studies confirm that chlorides ions are inhibitors of this enzyme at, physiologically relevant concentrations.
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Taspase1 catalyzes the proteolytic processing of the mixed lineage leukemia (MLL) nuclear protein, which is required for maintaining Hox gene expression patterns. Chromosomal translocations of the MLL gene are associated with leukemia in infants. Taspase1, a threonine aspartase, is a member of the type 2 asparaginase family, but is the only protease in this family. We report here the crystal structures of human activated Taspase1 and its proenzyme, as well as the characterization of the effects of mutations in the active site region using a newly developed fluorogenic assay. The structure of Taspase1 has significant differences from other asparaginases, especially near the active site. Mutation of the catalytic nucleophile, Thr234, abolishes autocatalytic processing in cis but does not completely block proteolysis in trans. The structure unexpectedly showed the binding of a chloride ion in the active site, and our kinetic studies confirm that chlorides ions are inhibitors of this enzyme at physiologically relevant concentrations.
==About this Structure==
==About this Structure==
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2A8M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with CL as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2A8M OCA].
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2A8M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A8M OCA].
==Reference==
==Reference==
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[[Category: Homo sapiens]]
[[Category: Homo sapiens]]
[[Category: Single protein]]
[[Category: Single protein]]
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[[Category: Dunn, B.M.]]
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[[Category: Dunn, B M.]]
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[[Category: Khan, J.A.]]
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[[Category: Khan, J A.]]
[[Category: Tong, L.]]
[[Category: Tong, L.]]
[[Category: CL]]
[[Category: CL]]
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[[Category: taspase]]
[[Category: taspase]]
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''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 12 20:47:30 2007''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:24:51 2008''

Revision as of 14:24, 21 February 2008

Image:2a8m.gif

2a8m, resolution 2.60Å

Drag the structure with the mouse to rotate

Crystal Structure of Human Taspase1 (T234S mutant)

Overview

Taspase1 catalyzes the proteolytic processing of the mixed lineage leukemia (MLL) nuclear protein, which is required for maintaining Hox gene expression patterns. Chromosomal translocations of the MLL gene are associated with leukemia in infants. Taspase1, a threonine aspartase, is a member of the type 2 asparaginase family, but is the only protease in this family. We report here the crystal structures of human activated Taspase1 and its proenzyme, as well as the characterization of the effects of mutations in the active site region using a newly developed fluorogenic assay. The structure of Taspase1 has significant differences from other asparaginases, especially near the active site. Mutation of the catalytic nucleophile, Thr234, abolishes autocatalytic processing in cis but does not completely block proteolysis in trans. The structure unexpectedly showed the binding of a chloride ion in the active site, and our kinetic studies confirm that chlorides ions are inhibitors of this enzyme at physiologically relevant concentrations.

About this Structure

2A8M is a Single protein structure of sequence from Homo sapiens with as ligand. Full crystallographic information is available from OCA.

Reference

Crystal structure of human Taspase1, a crucial protease regulating the function of MLL., Khan JA, Dunn BM, Tong L, Structure. 2005 Oct;13(10):1443-52. PMID:16216576

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