1pa1: Difference between revisions
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'''Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B''' | {{Structure | ||
|PDB= 1pa1 |SIZE=350|CAPTION= <scene name='initialview01'>1pa1</scene>, resolution 1.6Å | |||
|SITE= | |||
|LIGAND= <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene> and <scene name='pdbligand=CL:CHLORIDE ION'>CL</scene> | |||
|ACTIVITY= [http://en.wikipedia.org/wiki/Protein-tyrosine-phosphatase Protein-tyrosine-phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.48 3.1.3.48] | |||
|GENE= | |||
}} | |||
'''Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B''' | |||
==Overview== | ==Overview== | ||
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==About this Structure== | ==About this Structure== | ||
1PA1 is a [ | 1PA1 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PA1 OCA]. | ||
==Reference== | ==Reference== | ||
Functional characterization and crystal structure of the C215D mutant of protein-tyrosine phosphatase-1B., Romsicki Y, Scapin G, Beaulieu-Audy V, Patel S, Becker JW, Kennedy BP, Asante-Appiah E, J Biol Chem. 2003 Aug 1;278(31):29009-15. Epub 2003 May 13. PMID:[http:// | Functional characterization and crystal structure of the C215D mutant of protein-tyrosine phosphatase-1B., Romsicki Y, Scapin G, Beaulieu-Audy V, Patel S, Becker JW, Kennedy BP, Asante-Appiah E, J Biol Chem. 2003 Aug 1;278(31):29009-15. Epub 2003 May 13. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/12748196 12748196] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Protein-tyrosine-phosphatase]] | [[Category: Protein-tyrosine-phosphatase]] | ||
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[[Category: phosphatase]] | [[Category: phosphatase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Mar 20 13:21:50 2008'' | ||
Revision as of 11:21, 20 March 2008
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| 1pa1, resolution 1.6Å | |||||||||||||
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| Ligands: | MG and CL | ||||||||||||
| Activity: | Protein-tyrosine-phosphatase, with EC number 3.1.3.48 | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B
Overview
We have characterized the C215D active-site mutant of protein-tyrosine phosphatase-1B (PTP-1B) and solved the crystal structure of the catalytic domain of the apoenzyme to a resolution of 1.6 A. The mutant enzyme displayed maximal catalytic activity at pH approximately 4.5, which is significantly lower than the pH optimum of 6 for wild-type PTP-1B. Although both forms of the enzyme exhibited identical Km values for hydrolysis of p-nitrophenyl phosphate at pH 4.5 and 6, the kcat values of C215D were approximately 70- and approximately 7000-fold lower than those of wild-type PTP-1B, respectively. Arrhenius plots revealed that the mutant and wild-type enzymes displayed activation energies of 61 +/- 1 and 18 +/- 2 kJ/mol, respectively, at their pH optima. Unlike wild-type PTP-1B, C215D-mediated p-nitrophenyl phosphate hydrolysis was inactivated by 1,2-epoxy-3-(p-nitrophenoxy)propane, suggesting a direct involvement of Asp215 in catalysis. Increasing solvent microviscosity with sucrose (up to 40% (w/v)) caused a significant decrease in kcat/Km of the wild-type enzyme, but did not alter the catalytic efficiency of the mutant protein. Structurally, the apoenzyme was identical to wild-type PTP-1B, aside from the flexible WPD loop region, which was in both "open" and "closed" conformations. At physiological pH, the C215D mutant of PTP-1B should be an effective substrate-trapping mutant that can be used to identify cellular substrates of PTP-1B. In addition, because of its insensitivity to oxidation, this mutant may be used for screening fermentation broth and other natural products to identify inhibitors of PTP-1B.
Disease
Known diseases associated with this structure: Abdominal body fat distribution, modifier of OMIM:[176885], Insulin resistance, susceptibility to OMIM:[176885]
About this Structure
1PA1 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Functional characterization and crystal structure of the C215D mutant of protein-tyrosine phosphatase-1B., Romsicki Y, Scapin G, Beaulieu-Audy V, Patel S, Becker JW, Kennedy BP, Asante-Appiah E, J Biol Chem. 2003 Aug 1;278(31):29009-15. Epub 2003 May 13. PMID:12748196
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