Pannifer, A. D. B., Flint, A. J., Tonks, N. K., Barford, D. (April 1998) Visualization of the cysteinyl-phosphate intermediate of a protein-tyrosine phosphatase by X-ray crystallography. Journal of Biological Chemistry, 273 (17). pp. 10454-10462. ISSN 0021-9258
Abstract
Protein-tyrosine phosphatases (PTPs) are signal transduction enzymes that catalyze the dephosphorylation of phosphotyrosine residues via the formation of a transient cysteinyl-phosphate intermediate, The mechanism of hydrolysis of this intermediate has been examined by generating a Gln-262 --> Ala mutant of PTP1B, which allows the accumulation and trapping of the intermediate within a PTP1B crystal. The structure of the intermediate at 2.5-Angstrom resolution reveals that a conformationally flexible loop (the WPD loop) is closed over the entrance to the catalytic site, sequestering the phosphocysteine intermediate and catalytic site water molecules and preventing nonspecific phosphoryltransfer reactions to extraneous phosphoryl accepters. One of the catalytic site water molecules, the likely nucleophile, forms a hydrogen bond to the putative catalytic base, Asp-181. In the wild-type enzyme, the nucleophilic water molecule would be coordinated by the side chain of Gln-262, In combination with our previous structural data, we can now visualize each of the reaction steps of the PTP catalytic pathway. The hydrolysis of the cysteinyl-phosphate intermediate of PTPs is reminiscent of GTP hydrolysis by the GTPases, in that both families of enzymes utilize an invariant Gin residue to coordinate the attacking nucleophilic water molecule.
| Item Type: | Paper |
|---|---|
| Uncontrolled Keywords: | CRYSTAL-STRUCTURE HYDROLYSIS MECHANISM 1B PURIFICATION CATALYSIS DOMAIN TUMORS MOTIF GTP |
| Subjects: | bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes bioinformatics > genomics and proteomics > genetics & nucleic acid processing > protein structure, function, modification > protein types > enzymes > protein tyrosine phosphatase Investigative techniques and equipment > x ray crystallography |
| CSHL Authors: | |
| Communities: | CSHL labs > Tonks lab |
| Depositing User: | Matt Covey |
| Date: | April 1998 |
| Date Deposited: | 18 Dec 2013 17:19 |
| Last Modified: | 18 Dec 2013 17:19 |
| Related URLs: | |
| URI: | https://repository.cshl.edu/id/eprint/29031 |
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