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| | {{STRUCTURE_1d2a| PDB=1d2a | SCENE= }} | | {{STRUCTURE_1d2a| PDB=1d2a | SCENE= }} |
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| - | '''CRYSTAL STRUCTURE OF A YEAST LOW MOLECULAR WEIGHT PROTEIN TYROSINE PHOSPHATASE (LTP1) COMPLEXED WITH THE ACTIVATOR ADENINE'''
| + | ===CRYSTAL STRUCTURE OF A YEAST LOW MOLECULAR WEIGHT PROTEIN TYROSINE PHOSPHATASE (LTP1) COMPLEXED WITH THE ACTIVATOR ADENINE=== |
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| - | ==Overview==
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| - | Although the activation of low-molecular weight protein tyrosine phosphatases by certain purines and purine derivatives was first described three decades ago, the mechanism of this rate enhancement was unknown. As an example, adenine activates the yeast low-molecular weight protein tyrosine phosphatase LTP1 more than 30-fold. To examine the structural and mechanistic basis of this phenomenon, we have determined the crystal structure of yeast LTP1 complexed with adenine. In the crystal structure, an adenine molecule is found bound in the active site cavity, sandwiched between the side chains of two large hydrophobic residues at the active site. Hydrogen bonding to the side chains of other active site residues, as well as some water-mediated hydrogen bonds, also helps to fix the position of the bound adenine molecule. An ordered water was found in proximity to the bound phosphate ion present in the active site, held by hydrogen bonding to N3 of adenine and Odelta1 of Asp-132. On the basis of the crystal structure, we propose that this water molecule is the nucleophile that participates in the dephosphorylation of the phosphoenzyme intermediate. Solvent isotope effect studies show that there is no rate-determining transfer of a solvent-derived proton in the transition state for the dephosphorylation of the phosphoenzyme intermediate. Such an absence of general base catalysis of water attack is consistent with the stability of the leaving group, namely, the thiolate anion of Cys-13. Consequently, adenine activates the enzyme by binding and orienting a water nucleophile in proximity to the phosphoryl group of the phosphoenzyme intermediate, thus increasing the rate of the dephosphorylation step, a step that is normally the rate-limiting step of this enzymatic reaction.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_10684601}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 10684601 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_10684601}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Ltp1]] | | [[Category: Ltp1]] |
| | [[Category: Tyrosine phosphatase]] | | [[Category: Tyrosine phosphatase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:22:07 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 22:10:58 2008'' |
Revision as of 19:11, 30 June 2008
Template:STRUCTURE 1d2a
CRYSTAL STRUCTURE OF A YEAST LOW MOLECULAR WEIGHT PROTEIN TYROSINE PHOSPHATASE (LTP1) COMPLEXED WITH THE ACTIVATOR ADENINE
Template:ABSTRACT PUBMED 10684601
About this Structure
1D2A is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Structural and mechanistic basis for the activation of a low-molecular weight protein tyrosine phosphatase by adenine., Wang S, Stauffacher CV, Van Etten RL, Biochemistry. 2000 Feb 15;39(6):1234-42. PMID:10684601
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