PROTEIN THERMOSTABILIZATION BY PROLINE SUBSTITUTIONS

Citation
K. Watanabe et Y. Suzuki, PROTEIN THERMOSTABILIZATION BY PROLINE SUBSTITUTIONS, Journal of molecular catalysis. B, Enzymatic, 4(4), 1998, pp. 167-180
Citations number
81
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Chemistry Physical
ISSN journal
1381-1177
Volume
4
Issue
4
Year of publication
1998
Pages
167 - 180
Database
ISI
SICI code
1381-1177(1998)4:4<167:PTBPS>2.0.ZU;2-F
Abstract
Many recent approaches involving site-directed mutants have succeeded in increasing the thermostability of proteins. It is well known that r eplacements with proline residues reduce the conformational degrees of freedom in the main polypeptide chain and thus can increase protein t hermostabilization. We have studied protein thermostabilization by int roducing proline substitutions in the homologous oligo-1,6-glucosidase s from various Bacillus strains which grow within different temperatur e ranges. As a consequence, the 'proline rule' was proposed for protei n thermostabilization. The principle of this rule is that an increase in the frequency of proline occurrence at beta-turns and/or an increas e in the total number of hydrophobic residues can enhance protein ther mostability. We have generated several lines of evidence supporting th e theory from the comparative analysis of oligo-1,6-glucosidases in th eir primary and secondary structures and molecular properties, the X-r ay crystal structure analysis of the Bacillus cereus oligo-1,6-glucosi dase, and the enhancement in thermostability of the oligo-l,6-glucosid ase by cumulative replacements with prolines. As a new finding from th e studies, two specific sites (second positions at beta-turns and N1 p ositions of alpha-helices) were found to be the most critical to prote in thermostabilization dependent on several structural prerequisites f or proline substitution. (C) 1998 Elsevier Science B.V. All rights res erved.