Hydrolysis of small peptide substrates parallels binding of chymotrypsin inhibitor 2 for mutants of subtilisin BPN'

FEBS Letters

Rheinnecker, Michael¹  Fersht, Alan R.¹  Eder, Jörg¹ 

[1] MRC Unit for Protein Function and Design, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK

关键词: Subtilisin;    Chymotrypsin inhibitor 2;    S4 pocket;    P4 substrate;    Linear free-energy relationship;    CI2;    chymotrypsin inhibitor 2;    SSI;    Streptomyces subtilisin inhibitor. Mutants are designated by the single letter code of the wild type amino acid followed by the residue number and the amino acid replacement;   

DOI  :  10.1016/0014-5793(93)80417-S

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Variants of subtilisin BPN' that possess improved specificity towards isoleucine compared with alanine at the P₄ position of small peptide substrates, were analysed for their ability to bind chymotrypsin inhibitor 2. The binding of the inhibitor with isoleucine (wild-type) and with alanine as the P₄ residue parallels the hydrolysis of tetrapeptide substrates. There is a linear relationship between the free energy of binding of the transition state of the substrate and the free energy of binding of the inhibitor with a slope of 2.0. The data suggest that the inhibitor uses predominantly ground state rather than transition state binding energy.

【 授权许可】

Unknown