2b4u: Difference between revisions

Revision as of 17:34, 21 February 2008

Structure of the C252S mutant of Selenomonas ruminantium PTP-like phytase

OverviewOverview

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 StructureAbout this Structure

2B4U 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.

ReferenceReference

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

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 ==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, (HCX(5)R) 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 P(6) and will produce Ins(2)P via a highly ordered series, of sequential dephosphorylations: D-Ins(1,2,4,5,6)P(5), Ins(2,4,5,6)P(4), D-Ins(2,4,5)P(3), and D-Ins(2,4)P(2). 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.
+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==
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 [[Category: Selenomonas ruminantium]]
 [[Category: Single protein]]
-[[Category: Gruninger, R.J.]]
+[[Category: Gruninger, R J.]]
-[[Category: Mosimann, S.C.]]
+[[Category: Mosimann, S C.]]
-[[Category: Selinger, L.B.]]
+[[Category: Selinger, L B.]]
 [[Category: CL]]
 [[Category: MLI]]
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 [[Category: ptp-like]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 14:28:01 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:34:10 2008''