Premium
Investigation of the role of the disulphide bond in the activity and structure of staphylococcal enterotoxin C1
Author(s) -
Hovde Carolyn J.,
Marr James C.,
Hoffmann Marcy L.,
Hackett Sean P.,
Chi Youngin,
Crum Kimberlee K.,
Stevens Dennis L.,
Stauffacher Cynthia V.,
Bohach Gregory A.
Publication year - 1994
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.1365-2958.1994.tb00481.x
Subject(s) - enterotoxin , biology , microbiology and biotechnology , staphylococcus aureus , staphylococcal infections , computational biology , bacteria , biochemistry , genetics , escherichia coli , gene
Summary The goal of this study was to Investigate the role of the disulphide bond of staphylococcal enterotoxin C1 (SEC1) in the structure and activity of the toxin. Mutants unable to form a disulphide bond were generated by substituting alanine or serine for cysteine at positions 93 and/or 110. Although we did not directly investigate the residues between the disulphide linkage, tryptic lability showed that significant native structure in the cystine loop is preserved in the absence of covalent bonding between residues 93 and 110. Since no correlation was observed between the behaviour of these mutants with regard to toxin stability, emesis and T cell proliferation, we conclude that SEC1 ‐induced emesis and T cell proliferation are dependent on separate regions of the molecule. The disulphide bond itself is not an absolute requirement for either activity. However, conformation within or adjacent to the loop is important for emesis. Although mutants with alanine substitutions were not emetic, those with serine substitutions retained this activity, suggesting that the disulphide linkage stabilizes a crucial conformation but can be replaced by residues which hydrogen bond.