1V1D
Nucleophilic and General Acid Catalysis at Physiological pH by a Designed Miniature Esterase
1V1D の概要
| エントリーDOI | 10.2210/pdb1v1d/pdb |
| 関連するPDBエントリー | 1BBA 1LJV |
| 分子名称 | PANCREATIC HORMONE (1 entity in total) |
| 機能のキーワード | hormone, cleavage on pair of basic residues, pancreas |
| 由来する生物種 | BOS TAURUS (BOVINE) |
| 細胞内の位置 | Secreted: P01302 |
| タンパク質・核酸の鎖数 | 1 |
| 化学式量合計 | 3688.11 |
| 構造登録者 | |
| 主引用文献 | Nicoll, A.,Allemann, R.K. Nucleophilic and General Acid Catalysis at Physiological Ph by a Designed Miniature Esterase Org.Biomol.Chem., 2:2175-, 2004 Cited by PubMed Abstract: 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. PubMed: 15280952DOI: 10.1039/B404730C 主引用文献が同じPDBエントリー |
| 実験手法 | SOLUTION NMR |
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