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| | {{STRUCTURE_1anc| PDB=1anc | SCENE= }} | | {{STRUCTURE_1anc| PDB=1anc | SCENE= }} |
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| - | '''ANIONIC TRYPSIN MUTANT WITH SER 214 REPLACED BY LYS'''
| + | ===ANIONIC TRYPSIN MUTANT WITH SER 214 REPLACED BY LYS=== |
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| - | ==Overview==
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| - | Much of the catalytic power of trypsin is derived from the unusual buried, charged side chain of Asp102. A polar cave provides the stabilization for maintaining the buried charge, and it features the conserved amino acid Ser214 adjacent to Asp102. Ser214 has been replaced with Ala, Glu, and Lys in rat anionic trypsin, and the consequences of these changes have been determined. Three-dimensional structures of the Glu and Lys variant trypsins reveal that the new 214 side chains are buried. The 2.2-A crystal structure (R = 0.150) of trypsin S214K shows that Lys214 occupies the position held by Ser214 and a buried water molecule in the buried polar cave. Lys214-N zeta is solvent inaccessible and is less than 5 A from the catalytic Asp102. The side chain of Glu214 (2.8 A, R = 0.168) in trypsin S214E shows two conformations. In the major one, the Glu carboxylate in S214E forms a hydrogen bond with Asp102. Analytical isoelectrofocusing results show that trypsin S214K has a significantly different isoelectric point than trypsin, corresponding to an additional positive charge. The kinetic parameter kcat demonstrates that, compared to trypsin, S214K has 1% of the catalytic activity on a tripeptide amide substrate and S214E is 44% as active. Electrostatic potential calculations provide corroboration of the charge on Lys214 and are consistent with the kinetic results, suggesting that the presence of Lys214 has disturbed the electrostatic potential of Asp102.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_1554694}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 1554694 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_1554694}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Serine protease]] | | [[Category: Serine protease]] |
| | [[Category: Trypsin]] | | [[Category: Trypsin]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 10:28:37 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 17:12:40 2008'' |
Revision as of 14:12, 30 June 2008
Template:STRUCTURE 1anc
ANIONIC TRYPSIN MUTANT WITH SER 214 REPLACED BY LYS
Template:ABSTRACT PUBMED 1554694
About this Structure
1ANC is a Single protein structure of sequence from Rattus rattus. Full crystallographic information is available from OCA.
Reference
Perturbing the polar environment of Asp102 in trypsin: consequences of replacing conserved Ser214., McGrath ME, Vasquez JR, Craik CS, Yang AS, Honig B, Fletterick RJ, Biochemistry. 1992 Mar 31;31(12):3059-64. PMID:1554694
Page seeded by OCA on Mon Jun 30 17:12:40 2008
