Premium
Conformational changes in diphtheria toxoids
Author(s) -
Bigio Massimo,
Rossi Roberta,
Nucci Daniele,
Antoni Guido,
Rappuoli Rino,
Ratti Giulio
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)81060-8
Subject(s) - diphtheria toxin , chemistry , mutant , monoclonal antibody , diphtheria , corynebacterium diphtheriae , radioimmunoassay , conformational change , microbiology and biotechnology , toxin , biochemistry , antibody , stereochemistry , biology , virology , genetics , vaccination , gene
Monoclonal antibodies (Mab) were raised against CRM197, a non‐toxic mutant of diphtheria toxin (DT). The ability of four Mabs to bind DT and the six functional mutants CRM197, CRM176, CRM228, CRM1001, CRM45 and CRM30 was assessed by immunoblotting and by a radioimmunoassay in which the protein antigen in solution competes with labeled CRM197 for the Mab binding site. The results show that the peptides recognized by Mab11.3, Mab53 and Mab23 are accessible in the mutant molecules in solution but not when they are part of the native DT structure, which could therefore be described for this purpose as ‘closed’ in contrast with an ‘open’ conformation of CRM197, CRM176 and CRM228. In particular, the behaviour of Mab53 indicates that the single amino acid substitutions in the A fragments of CRM197 and CRM176 also affect the conformation of their B fragments.