2i42: Difference between revisions

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[[Image:2i42.gif|left|200px]]
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[[Image:2i42.png|left|200px]]


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{{STRUCTURE_2i42|  PDB=2i42  |  SCENE=  }}  
{{STRUCTURE_2i42|  PDB=2i42  |  SCENE=  }}  


'''Crystal structure of Yersinia protein tyrosine phosphatase complexed with vanadate, a transition state analogue'''
===Crystal structure of Yersinia protein tyrosine phosphatase complexed with vanadate, a transition state analogue===


==Overview==
Engineering site-specific amino acid substitutions into the protein-tyrosine phosphatase (PTPase) PTP1 and the dual-specific vaccinia H1-related phosphatase (VHR), has kinetically isolated the two chemical steps of the reaction and provided a rare opportunity for examining transition states and directly observing the phosphoenzyme intermediate. Changing serine to alanine in the active-site sequence motif HCXXGXXRS shifted the rate-limiting step from intermediate formation to intermediate hydrolysis. Using phosphorus 31P NMR, the covalent thiol-phosphate intermediate was directly observed during catalytic turnover. The importance of the conserved aspartic acid (D92 in VHR and D181 in PTP1) in both chemical steps was established. Kinetic analysis of D92N and D181N mutants indicated that aspartic acid acts as a general acid by protonating the leaving-group phenolic oxygen. Structure-reactivity experiments with native and aspartate mutant enzymes established that proton transfer is concomitant with P-O cleavage, such that no charge develops on the phenolic oxygen. Steady- and presteady-state kinetics, as well as NMR analysis of the double mutant D92N/S131A (VHR), suggested that the conserved aspartic acid functions as a general base during intermediate hydrolysis. As a general base, aspartate would activate a water molecule to facilitate nucleophilic attack. The amino acids involved in transition-state stabilization for cysteinylphosphate hydrolysis were confirmed by the x-ray structure of the Yersinia PTPase complexed with vanadate, a transition-state mimic that binds covalently to the active-site cysteine. Consistent with the NMR, x-ray, biochemical, and kinetic data, a unifying mechanism for catalysis is proposed.


==About this Structure==
==About this Structure==
2I42 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Yersinia_enterocolitica Yersinia enterocolitica]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I42 OCA].  
2I42 is a 1 chain structure of sequence from [http://en.wikipedia.org/wiki/Yersinia_enterocolitica Yersinia enterocolitica]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2I42 OCA].  


==Reference==
==Reference==
Visualization of intermediate and transition-state structures in protein-tyrosine phosphatase catalysis., Denu JM, Lohse DL, Vijayalakshmi J, Saper MA, Dixon JE, Proc Natl Acad Sci U S A. 1996 Mar 19;93(6):2493-8. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/8637902 8637902]
<ref group="xtra">PMID:8637902</ref><ref group="xtra">PMID:8528087</ref><ref group="xtra">PMID:8127855</ref><references group="xtra"/>
[[Category: Protein-tyrosine-phosphatase]]
[[Category: Protein-tyrosine-phosphatase]]
[[Category: Single protein]]
[[Category: Yersinia enterocolitica]]
[[Category: Yersinia enterocolitica]]
[[Category: Saper, M A.]]
[[Category: Saper, M A.]]
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[[Category: Vanadate]]
[[Category: Vanadate]]
[[Category: Yersinia ptpase]]
[[Category: Yersinia ptpase]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Feb 17 08:18:24 2009''

Revision as of 06:18, 17 February 2009

File:2i42.png

Template:STRUCTURE 2i42

Crystal structure of Yersinia protein tyrosine phosphatase complexed with vanadate, a transition state analogue

About this Structure

2I42 is a 1 chain structure of sequence from Yersinia enterocolitica. Full crystallographic information is available from OCA.

Reference

  1. Denu JM, Lohse DL, Vijayalakshmi J, Saper MA, Dixon JE. Visualization of intermediate and transition-state structures in protein-tyrosine phosphatase catalysis. Proc Natl Acad Sci U S A. 1996 Mar 19;93(6):2493-8. PMID:8637902
  2. Schubert HL, Fauman EB, Stuckey JA, Dixon JE, Saper MA. A ligand-induced conformational change in the Yersinia protein tyrosine phosphatase. Protein Sci. 1995 Sep;4(9):1904-13. PMID:8528087
  3. Zhang ZY, Wang Y, Dixon JE. Dissecting the catalytic mechanism of protein-tyrosine phosphatases. Proc Natl Acad Sci U S A. 1994 Mar 1;91(5):1624-7. PMID:8127855

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