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Genetic exchange of the S2 and S3 subunits in pertussis toxin
Author(s) -
Raze Dominique,
Veithen Alex,
Sato Hiroko,
Antoine Rudy,
Menozzi Franco D.,
Locht Camille
Publication year - 2006
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.1365-2958.2006.05165.x
Subject(s) - biology , bordetella pertussis , pertussis toxin , toxin , chinese hamster ovary cell , protein subunit , secretion , bordetella , exotoxin , diphtheria toxin , whooping cough , microbiology and biotechnology , biochemistry , genetics , receptor , g protein , virology , gene , bacteria , vaccination
Summary Bordetella pertussis , the causative agent of whooping cough, produces a complex hetero‐oligomeric exotoxin, named pertussis toxin (PTX), which is responsible for several of the clinical manifestations associated with whooping cough. The toxin is composed of five dissimilar subunits, named S1 through S5 and arranged in a hexameric structure with a 1S1:1S2:1S3:2S4:1S5 stoichiometry. Although S2 and S3 share 70% amino acid identity, these two subunits were previously thought not to be able to substitute for each other in toxin assembly/secretion and the biological activities of PTX. Here, we show that toxin analogues containing two S3 subunits and lacking S2 (PTXΔS2), or containing two S2 subunits and lacking S3 (PTXΔS3), can be produced, assembled and secreted by B. pertussis strains, in which the S2‐encoding cistron or the S3‐coding cistrons have been inactivated by internal in‐frame deletions that avoid downstream effects. In fact, PTXΔS3 was produced in higher amounts in the bacterial culture supernatants than natural PTX, whereas PTXΔS2 was produced in lower amounts than PTX. The action of the toxin analogues on the clustering of Chinese Hamster Ovary cells was also affected differentially by the S2–S3 substitution. These toxin analogues constitute thus interesting probes for the study of cellular functions, in particular immune cell functions, for which natural PTX has already shown its usefulness.