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ADP‐ribosylation by Clostridium botulinum C3 exoenzyme increases steady‐state GTPase activities of recombinant rhoA and rhoB proteins
Author(s) -
Mohr Christiane,
Koch Gertrud,
Just Ingo,
Aktories Klaus
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80335-e
Subject(s) - rhoa , gtpase , gtp' , clostridium botulinum , adp ribosylation , chemistry , biochemistry , rhob , nad+ kinase , enzyme , toxin , signal transduction
ADP‐ribosylation of recombinant rhoA and rhoB proteins by Clostridium botulinum C3 exoenzyme increased steady‐state GTP hydrolysis by 50 to 80%. ADP‐ribosylation and increase in GTP hydrolysis occurred at similar concentrations of C3, depended on the presence of NAD and were prevented by anti‐C3 antibody or heat inactivation of C3. In contrast, GTP hydrolysis by Ile‐41 rhoA or Ha‐ras, which are no substrates for the transferase, were not affected by C3. ADP‐ribosylation facilitated the [ 3 H]GDP release and subsequently, the binding of [ 3 H]GTP to rhoA. The data indicate that the increase in the steady‐state GTPase activity by ADP‐ribosylation is caused by increasing the rate of GDP release which is suggested to be the rate limiting step of the GTPase cycle of the small GTP‐binding proteins.