Evidence that Arg-295, Glu-378, and Glu-380 are active-site residues of the ADP-ribosyltransferase activity of iota toxin.
FEBS Lett
; 395(2-3): 191-4, 1996 Oct 21.
Article
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| MEDLINE
| ID: mdl-8898093
ABSTRACT
The active site of the enzymatic component (Ia) of the Clostridium perfringens iota toxin has been studied by site-directed mutagenesis. Sequence alignment showed that Ia and C3 enzymes display a segment in their C-terminal part which is homologous to that forming the active domain of pertussis toxin, cholera toxin, and Escherichia coli thermolabile toxins. This structure consists of a beta-strand and an alpha-helix which forms the NAD-binding cavity and which is flanked by two catalytic spatially conserved residues involved in catalysis [Domenighini et al. (1994) Mol. Microbiol. 14, 41-50]. Substitutions (Arg-295-Lys, Glu-378-Ala, Glu-380-Asp, and Glu-380-Ala) induced a drastic decrease in ADP-ribosylation and cytotoxic activities, while substitution of the adjacent Arg (Arg-296-Lys) only partially affected the enzymatic activity and cytotoxicity. These results indicate that Arg-295, Glu-378 and Glu-380 of Ia are involved in the ADP-ribosylation activity which is essential for the morphological changes of cells treated with iota toxin.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Arginina
/
Toxinas Bacterianas
/
Poli(ADP-Ribosa) Polimerasas
/
Clostridium perfringens
/
ADP Ribosa Transferasas
/
Ácido Glutámico
Límite:
Animals
Idioma:
En
Revista:
FEBS Lett
Año:
1996
Tipo del documento:
Article
País de afiliación:
Francia