Structure of a specific acyl-enzyme complex formed between β-casomorphin-7 and porcine pancreatic elastase

被引：0
作者：
Rupert C. Wilmouth
Ian J. Clifton
Carol V. Robinson
Peter L. Roach
Robin T. Aplin
Nicholas J. Westwood
Janos Hajdu
Christopher J. Schofield
机构：
[1] The Oxford Centre for Molecular Sciences,Department of Biochemistry
[2] The Dyson Perrins Laboratory,undefined
[3] Laboratory of Molecular Biophysics,undefined
[4] Uppsala University,undefined
来源：
Nature Structural Biology | 1997年 / 4卷
关键词：
D O I：
暂无
中图分类号：
学科分类号：
摘要：
Mass spectrometric screening reveals that an unmodified natural heptapeptide—human β-casomorphin-7, an internal sequence of human β-casein that possesses opioid-like activity—reacts with porcine pancreatic elastase to form an unusually stable acyl-enzyme complex at low pH. X-ray crystallographic analysis (to 1.9 Å resolution) at pH 5 shows continuous electron density linking the C-terminal isoleucine of β-casomorphin-7 to Ser 195 through an ester bond. The structure reveals a well defined water molecule (Wat 317), equidistant between the carbon of the ester carbonyl and Nε2 of His 57. Deprotonation of Wat 317 will produce a hydroxide ion positioned to attack the ester carbonyl through the favoured Bürgi-Dunitz trajectory.
引用
收藏
页码：456 / 462
页数：6
相关论文
共 104 条
[11]  
Dixon MM(1994)Direct structural observation of an acyl-enzyme intermediate in the hydrolysis of an ester substrate by elastase Biochemistry 33 9285-587
[12]  
Matthews BW(1994)A crystallographic re-investigation into the structure of J. Mol. Biol. 241 574-3246
[13]  
Harel M(1992) proteinase A reveals an acyl-enzyme intermediate J. Am. Chem. Soc. 114 3241-214
[14]  
Su C-T(1990)Electrospray mass spectrometry of poly(ethylene glycols) with molecular weights up to five million FEBS Lett. 277 212-204
[15]  
Frolow F(1991)Use of electrospray mass-spectrometry to directly observe an acyl-enzyme intermediate in beta-lactamase catalysis FEBS Lett. 292 201-10912
[16]  
Silman I(1993)Some electrospray mass spectrometric evidence for the existence of covalent O-acyl enzyme intermediates Tetrahedron 49 10903-5138
[17]  
Sussman JL(1984)An investigation into the mechanism of elastase inhibition by cephalosporins using electrospray ionisation mass spectrometry J. Biol. Chem. 259 5132-472
[18]  
Dixon MM(1980)Human β-casein Biochemistry 19 468-38
[19]  
Brennan RG(1988)Substrate specificity of human pancreatic elastase 2 Acta Cryst. B44 26-4
[20]  
Matthews BW(1990)Structure of native porcine pancreatic elastase at 1.65 Å resolution Peptides 11 1-5501
12345678910