1w2f: Difference between revisions
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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, 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 | 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== | ||
1W2F is a | 1W2F 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 SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Transferase Transferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.7.127 2.1.7.127] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1W2F OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: transferase]] | [[Category: transferase]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:48:46 2007'' | ||
