Effects of mutations on enzyme activity and immunoreactivity of the S1 subunit of pertussis toxin.
By introducing a series of six different substitutions at and around position 9, we investigated the structural requirements of the amino-terminal region of the S1 subunit of pertussis toxin for both enzyme activity and immunoreactivity. All mutant S1 analogs with a substitution at this location exhibited severely decreased ADP-ribosyltransferase activity (range, 400- to 2,500-fold). In contrast, alteration of arginine 58 had considerably less effect. The reactivity of the mutant molecules with monoclonal antibody 1B7 varied with the nature of the substitution. These findings indicate an absolute requirement for the presence of an arginine residue at position 9 for the maintenance of efficient ADP-ribosyltransferase activity and illustrate the specific participation of vicinal residues in the formation of the protective epitope.
Lobet
Y
Y
Laboratory of Pathobiology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana 59840.
Cieplak
W
W
Smith
S G
SG
Keith
J M
JM
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D004252:DNA Mutational Analysis; D008969:Molecular Sequence Data; D010430:Pentosyltransferases / Q000378:metabolism*; D037342:Pertussis Toxin; D013329:Structure-Activity Relationship; D015293:Transducin / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000235:genetics* / Q000276:immunology / Q000378:metabolism
D000907:Antibodies, Bacterial; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D010430:Pentosyltransferases; D037342:Pertussis Toxin; D015293:Transducin