2b4p
From Proteopedia
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'''Structure of the D223N mutant of Selenomonas ruminantium PTP-like phytase''' | '''Structure of the D223N mutant of Selenomonas ruminantium PTP-like phytase''' | ||
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[[Category: Mosimann, S C.]] | [[Category: Mosimann, S C.]] | ||
[[Category: Selinger, L B.]] | [[Category: Selinger, L B.]] | ||
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| - | [[Category: | + | [[Category: Ptp-like]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 19:51:15 2008'' | |
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Revision as of 16:51, 3 May 2008
Structure of the D223N mutant of Selenomonas ruminantium PTP-like phytase
Overview
PhyA from Selenomonas ruminantium (PhyAsr), is a bacterial protein tyrosine phosphatase (PTP)-like inositol polyphosphate phosphatase (IPPase) that is distantly related to known PTPs. PhyAsr has a second substrate binding site referred to as a standby site and the P-loop (HCX5R) has been observed in both open (inactive) and closed (active) conformations. Site-directed mutagenesis and kinetic and structural studies indicate PhyAsr follows a classical PTP mechanism of hydrolysis and has a broad specificity toward polyphosphorylated myo-inositol substrates, including phosphoinositides. Kinetic and molecular docking experiments demonstrate PhyAsr preferentially cleaves the 3-phosphate position of Ins P6 and will produce Ins(2)P via a highly ordered series of sequential dephosphorylations: D-Ins(1,2,4,5,6)P5, Ins(2,4,5,6)P4, D-Ins(2,4,5)P3, and D-Ins(2,4)P2. The data support a distributive enzyme mechanism and suggest the PhyAsr standby site is involved in the recruitment of substrate. Structural studies at physiological pH and high salt concentrations demonstrate the "closed" or active P-loop conformation can be induced in the absence of substrate. These results suggest PhyAsr should be reclassified as a D-3 myo-inositol hexakisphosphate phosphohydrolase and suggest the PhyAsr reaction mechanism is more similar to that of PTPs than previously suspected.
About this Structure
2B4P is a Single protein structure of sequence from Selenomonas ruminantium. Full crystallographic information is available from OCA.
Reference
Kinetic and structural analysis of a bacterial protein tyrosine phosphatase-like myo-inositol polyphosphatase., Puhl AA, Gruninger RJ, Greiner R, Janzen TW, Mosimann SC, Selinger LB, Protein Sci. 2007 Jul;16(7):1368-78. Epub 2007 Jun 13. PMID:17567745 Page seeded by OCA on Sat May 3 19:51:15 2008
