2b4p
From Proteopedia
(New page: 200px<br /><applet load="2b4p" size="350" color="white" frame="true" align="right" spinBox="true" caption="2b4p, resolution 1.81Å" /> '''Structure of the D22...) |
|||
| Line 4: | Line 4: | ||
==Overview== | ==Overview== | ||
| - | PhyA from Selenomonas ruminantium (PhyAsr), is a bacterial protein | + | 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== | ==About this Structure== | ||
| Line 14: | Line 14: | ||
[[Category: Selenomonas ruminantium]] | [[Category: Selenomonas ruminantium]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Gruninger, R | + | [[Category: Gruninger, R J.]] |
| - | [[Category: Mosimann, S | + | [[Category: Mosimann, S C.]] |
| - | [[Category: Selinger, L | + | [[Category: Selinger, L B.]] |
[[Category: CL]] | [[Category: CL]] | ||
[[Category: MLI]] | [[Category: MLI]] | ||
| Line 22: | Line 22: | ||
[[Category: ptp-like]] | [[Category: ptp-like]] | ||
| - | ''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 16:34:08 2008'' |
Revision as of 14:34, 21 February 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 with and as ligands. Active as 5-phytase, with EC number 3.1.3.72 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 Thu Feb 21 16:34:08 2008
