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1w2c
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Mammalian cells produce a variety of inositol phosphates (InsPs), including Ins(1,4,5)P3 that serves both as a second messenger and as a | + | Mammalian cells produce a variety of inositol phosphates (InsPs), including Ins(1,4,5)P3 that serves both as a second messenger and as a substrate for inositol polyphosphate kinases (IPKs), which further phosphorylate it. We report the structure of an IPK, the human Ins(1,4,5)P3 3-kinase-A, both free and in complexes with substrates and products. This enzyme catalyzes transfer of a phosphate from ATP to the 3-OH of Ins(1,4,5)P3, and its X-ray crystal structure provides a template for understanding a broad family of InsP kinases. The catalytic domain consists of three lobes. The N and C lobes bind ATP and resemble protein and lipid kinases, despite insignificant sequence similarity. The third lobe binds inositol phosphate and is a unique four-helix insertion in the C lobe. This lobe embraces all of the phosphates of Ins(1,4,5)P3 in a positively charged pocket, explaining the enzyme's substrate specificity and its inability to phosphorylate PtdIns(4,5)P2, the membrane-resident analog of Ins(1,4,5)P3. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Transferase]] | [[Category: Transferase]] | ||
[[Category: Gonzalez, B.]] | [[Category: Gonzalez, B.]] | ||
| - | [[Category: Irvine, R | + | [[Category: Irvine, R F.]] |
| - | [[Category: Schell, M | + | [[Category: Schell, M J.]] |
| - | [[Category: Williams, R | + | [[Category: Williams, R L.]] |
[[Category: ANP]] | [[Category: ANP]] | ||
[[Category: I3P]] | [[Category: I3P]] | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:39:43 2008'' |
Revision as of 13:39, 21 February 2008
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HUMAN INOSITOL (1,4,5) TRISPHOSPHATE 3-KINASE COMPLEXED WITH MN2+/AMPPNP/INS(1,4,5)P3
Overview
Mammalian cells produce a variety of inositol phosphates (InsPs), including Ins(1,4,5)P3 that serves both as a second messenger and as a substrate for inositol polyphosphate kinases (IPKs), which further phosphorylate it. We report the structure of an IPK, the human Ins(1,4,5)P3 3-kinase-A, both free and in complexes with substrates and products. This enzyme catalyzes transfer of a phosphate from ATP to the 3-OH of Ins(1,4,5)P3, and its X-ray crystal structure provides a template for understanding a broad family of InsP kinases. The catalytic domain consists of three lobes. The N and C lobes bind ATP and resemble protein and lipid kinases, despite insignificant sequence similarity. The third lobe binds inositol phosphate and is a unique four-helix insertion in the C lobe. This lobe embraces all of the phosphates of Ins(1,4,5)P3 in a positively charged pocket, explaining the enzyme's substrate specificity and its inability to phosphorylate PtdIns(4,5)P2, the membrane-resident analog of Ins(1,4,5)P3.
About this Structure
1W2C is a Single protein structure of sequence from Homo sapiens with , , and as ligands. Active as Transferase, with EC number 2.1.7.127 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Structure of a human inositol 1,4,5-trisphosphate 3-kinase: substrate binding reveals why it is not a phosphoinositide 3-kinase., Gonzalez B, Schell MJ, Letcher AJ, Veprintsev DB, Irvine RF, Williams RL, Mol Cell. 2004 Sep 10;15(5):689-701. PMID:15350214
Page seeded by OCA on Thu Feb 21 15:39:43 2008
Categories: Homo sapiens | Single protein | Transferase | Gonzalez, B. | Irvine, R F. | Schell, M J. | Williams, R L. | ANP | I3P | MN | SO4 | Amppnp | Inositol phosphate kinase | Ip3
