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1v1d

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[[Image:1v1d.gif|left|200px]]
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{{Seed}}
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[[Image:1v1d.png|left|200px]]
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{{STRUCTURE_1v1d| PDB=1v1d | SCENE= }}
{{STRUCTURE_1v1d| PDB=1v1d | SCENE= }}
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'''NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE'''
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===NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE===
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==Overview==
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A 31-residue peptide (Art-Est) was designed to catalyse the hydrolysis of p-nitrophenyl esters through histidine catalysis on the solvent exposed face of the alpha-helix of bovine pancreatic polypeptide. NMR spectroscopy indicated that Art-Est adopted a stable 3-dimensional structure in solution. Art-Est was an efficient catalyst with second order rate constants of up to 0.050 M(-1) s(-1). The activity of Art-Est was a consequence of the increased nucleophilicity of His-22, which had a reduced pK(a) value of 5.5 as a consequence of its interaction with His-18 and the positively charged Arg-25 and Arg-26. Mass spectrometry and NMR spectroscopy confirmed that the Art-Est catalysed hydrolysis of p-nitrophenyl esters proceeded through an acyl-enzyme intermediate. A solvent kinetic isotope effect of 1.8 indicated that the transition state preceding the acyl intermediate was stabilised through interaction with the protonated side-chain of His-18 and indicated a reaction mechanism similar to that generally observed for natural esterases. The involvement in the reaction of two histidine residues with different pK(a) values led to a bell-shaped dependence of the reaction rate on the pH of the solution. The catalytic behaviour of Art-Est indicated that designed miniature enzymes can act in a transparent mechanism based fashion with enzyme-like behaviour through the interplay of several amino acid residues.
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The line below this paragraph, {{ABSTRACT_PUBMED_15280952}}, adds the Publication Abstract to the page
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(as it appears on PubMed at http://www.pubmed.gov), where 15280952 is the PubMed ID number.
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{{ABSTRACT_PUBMED_15280952}}
==About this Structure==
==About this Structure==
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1V1D is a [[Single protein]] structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V1D OCA].
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1V1D is a [[Single protein]] structure. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V1D OCA].
==Reference==
==Reference==
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[[Category: Hormone]]
[[Category: Hormone]]
[[Category: Pancrea]]
[[Category: Pancrea]]
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 11:57:58 2008''
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''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 00:33:12 2008''

Revision as of 21:33, 27 July 2008

Image:1v1d.png

Template:STRUCTURE 1v1d

NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE

Template:ABSTRACT PUBMED 15280952

About this Structure

1V1D is a Single protein structure. Full experimental information is available from OCA.

Reference

Nucleophilic and general acid catalysis at physiological pH by a designed miniature esterase., Nicoll AJ, Allemann RK, Org Biomol Chem. 2004 Aug 7;2(15):2175-80. Epub 2004 Jul 8. PMID:15280952

Page seeded by OCA on Mon Jul 28 00:33:12 2008

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