1v1d
From Proteopedia
(New page: 200px<br /><applet load="1v1d" size="450" color="white" frame="true" align="right" spinBox="true" caption="1v1d" /> '''NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT P...) |
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| - | [[Image:1v1d.gif|left|200px]]<br /><applet load="1v1d" size=" | + | [[Image:1v1d.gif|left|200px]]<br /><applet load="1v1d" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1v1d" /> | caption="1v1d" /> | ||
'''NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE'''<br /> | '''NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | A 31-residue peptide (Art-Est) was designed to catalyse the hydrolysis of | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1V1D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http:// | + | 1V1D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/ ]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1V1D OCA]. |
==Reference== | ==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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15280952 15280952] | 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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=15280952 15280952] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Allemann, R | + | [[Category: Allemann, R K.]] |
[[Category: Nicoll, A.]] | [[Category: Nicoll, A.]] | ||
[[Category: cleavage on pair of basic residues]] | [[Category: cleavage on pair of basic residues]] | ||
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[[Category: pancreas]] | [[Category: pancreas]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:30:33 2008'' |
Revision as of 13:30, 21 February 2008
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NUCLEOPHILIC AND GENERAL ACID CATALYSIS AT PHYSIOLOGICAL PH BY A DESIGNED MINIATURE ESTERASE
Overview
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.
About this Structure
1V1D is a Single protein structure of sequence from [1]. Full crystallographic 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
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