1pa1
From Proteopedia
(New page: 200px<br /> <applet load="1pa1" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pa1, resolution 1.6Å" /> '''Crystal structure of...) |
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caption="1pa1, resolution 1.6Å" /> | caption="1pa1, resolution 1.6Å" /> | ||
'''Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B'''<br /> | '''Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1PA1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with MG and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http:// | + | 1PA1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [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] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PA1 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: phosphatase]] | [[Category: phosphatase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 16:39:32 2008'' |
Revision as of 14:39, 15 February 2008
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Crystal structure of the C215D mutant of protein tyrosine phosphatase 1B
Contents |
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 with and as ligands. Active as Protein-tyrosine-phosphatase, with EC number 3.1.3.48 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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