1h6l
From Proteopedia
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| - | [[Image:1h6l.gif|left|200px]]<br /> | + | [[Image:1h6l.gif|left|200px]]<br /><applet load="1h6l" size="450" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1h6l" size="450" color="white" frame="true" align="right" spinBox="true" | + | |
caption="1h6l, resolution 1.8Å" /> | caption="1h6l, resolution 1.8Å" /> | ||
'''BETA-PROPELLER PHYTASE IN COMPLEX WITH PHOSPHATE AND CALCIUM IONS'''<br /> | '''BETA-PROPELLER PHYTASE IN COMPLEX WITH PHOSPHATE AND CALCIUM IONS'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1H6L is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_amyloliquefaciens Bacillus amyloliquefaciens] with CA and PO4 as [http://en.wikipedia.org/wiki/ligands ligands]. | + | 1H6L is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_amyloliquefaciens Bacillus amyloliquefaciens] with CA and PO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Known structural/functional Sites: <scene name='pdbsite=AC1:Structural Ca 401 Binding Site For Chain'>AC1</scene>, <scene name='pdbsite=AC2:Structural Ca 402 Binding Site For Chain'>AC2</scene>, <scene name='pdbsite=AC3:Structural Ca 403 Binding Site For Chain'>AC3</scene>, <scene name='pdbsite=AC4:Activity Ca 404 Binding Site For Chain A'>AC4</scene>, <scene name='pdbsite=AC5:Activity Ca 405 Binding Site For Chain A'>AC5</scene>, <scene name='pdbsite=AC6:Activity Ca 406 Binding Site For Chain A'>AC6</scene>, <scene name='pdbsite=AC7:Activity Ca 407 Binding Site For Chain A'>AC7</scene>, <scene name='pdbsite=AC8:Product Po4 501 Binding Site For Chain A'>AC8</scene> and <scene name='pdbsite=AC9:Product Po4 502 Binding Site For Chain A'>AC9</scene>. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1H6L OCA]. |
==Reference== | ==Reference== | ||
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[[Category: propeller]] | [[Category: propeller]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Tue Dec 18 16:04:00 2007'' |
Revision as of 13:54, 18 December 2007
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BETA-PROPELLER PHYTASE IN COMPLEX WITH PHOSPHATE AND CALCIUM IONS
Overview
BACKGROUND: Phytases hydrolyze phytic acid (myo-inositol-hexakisphosphate), to less-phosphorylated myo-inositol derivatives and inorganic phosphate., Phytases are used in animal feed to reduce phosphate pollution in the, environment. Recently, a thermostable, calcium-dependent Bacillus phytase, was identified that represents the first example of the beta propeller, fold exhibiting phosphatase activity. We sought to delineate the catalytic, mechanism and property of this enzyme. RESULTS: The crystal structure of, the enzyme in complex with inorganic phosphate reveals that two phosphates, and four calcium ions are tightly bound at the active site. Mutation of, the residues involved in the calcium chelation results in severe defects, in the enzyme's activity. One phosphate ion, chelating all of the four, calcium ions, is close to a water molecule bridging two of the bound, calcium ions. Fluoride ion, which is expected to replace this water, molecule, is an uncompetitive inhibitor of the enzyme. The enzyme is able, to hydrolyze any of the six phosphate groups of phytate. CONCLUSIONS: The, enzyme reaction is likely to proceed through a direct attack of the, metal-bridging water molecule on the phosphorous atom of a substrate and, the subsequent stabilization of the pentavalent transition state by the, bound calcium ions. The enzyme has two phosphate binding sites, the, "cleavage site", which is responsible for the hydrolysis of a substrate, and the "affinity site", which increases the binding affinity for, substrates containing adjacent phosphate groups. The existence of the two, nonequivalent phosphate binding sites explains the puzzling formation of, the alternately dephosphorylated myo-inositol triphosphates from phytate, and the hydrolysis of myo-inositol monophosphates.
About this Structure
1H6L is a Single protein structure of sequence from Bacillus amyloliquefaciens with CA and PO4 as ligands. Known structural/functional Sites: , , , , , , , and . Full crystallographic information is available from OCA.
Reference
Enzyme mechanism and catalytic property of beta propeller phytase., Shin S, Ha NC, Oh BC, Oh TK, Oh BH, Structure. 2001 Sep;9(9):851-8. PMID:11566134
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Categories: Bacillus amyloliquefaciens | Single protein | Ha, N.C. | Oh, B.H. | Shin, S. | CA | PO4 | Phosphatase | Phosphate | Phytase | Propeller
