1c0e: Difference between revisions

[[Image:1c0e.jpg|left|200px]]<br /><applet load="1c0e" size="350" color="white" frame="true" align="right" spinBox="true"  

The bovine protein tyrosine phosphatase (BPTP) is a member of the class of low-molecular weight protein tyrosine phosphatases (PTPases) found to be ubiquitous in mammalian cells. The catalytic site of BPTP contains a CX(5)R(S/T) phosphate-binding motif or P-loop (residues 12-19) which is the signature sequence for all PTPases. Ser19, the final residue of the P-loop motif, interacts with the catalytic Cys12 and participates in stabilizing the conformation of the active site through interactions with Asn15, also in the P-loop. Mutations at Ser19 result in an enzyme with altered kinetic properties with changes in the pK(a) of the neighboring His72. The X-ray structure of the S19A mutant enzyme shows that the general conformation of the P-loop is preserved. However, changes in the loop containing His72 result in a displacement of the His72 side chain that may explain the shift in the pK(a). In addition, it was found that in the crystal, the protein forms a dimer in which Tyr131 and Tyr132 from one monomer insert into the active site of the other monomer, suggesting a dual-tyrosine motif on target sites for this enzyme. Since the activity of this PTPase is reportedly regulated by phosphorylation at Tyr131 and Tyr132, the structure of this dimer may provide a model of a self-regulation mechanism for the low-molecular weight PTPases.

1C0E is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Acid_phosphatase Acid phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.2 3.1.3.2] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1C0E OCA].  

[[Category: Etten, R L.Van.]]

[[Category: Evans, B N.]]

[[Category: Stauffacher, C V.]]

[[Category: Tishmack, P A.]]

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