Premium
Nucleotide substitutions and small‐scale insertion produce size and antigenic variation in group A streptococcal M1 protein
Author(s) -
Harbaugh M. P.,
Podbielski A.,
Hügl S.,
Cleary P. P.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb01642.x
Subject(s) - biology , antigenic variation , nucleic acid sequence , genetics , epitope , nucleotide , insert (composites) , gene , serotype , strain (injury) , antigen , virology , anatomy , mechanical engineering , engineering
Summary The presence of M protein on the surface of group A streptococci (GAS) confers the ability of the cell to resist phagocytosis in the absence of type‐specific antibodies. It undergoes antigenic variation with more than 80 different serotypes having been defined. We have sequenced the M protein gene ( emm1.1 ) from strain CS190 and present evidence that individual nucleotide substitutions are responsible for sequence variation in the N ‐terminal non‐repeat region of emm1.1 and these substitutions have altered antibody recognition of opsonic epitopes. The N ‐terminal non‐repeat domains of two other closely related strains, 71‐155 and 76‐088, were found to have sequence identical to emm1.1 with the addition of a 21 bp insert. This study provides the first evidence that nucleotide substitutions and small insertions are responsible for size and antigenic variation in the N terminal non‐repeat domain of the M protein of GAS.