Identification of Glu173 as the critical amino acid residue for the ADP‐ribosyltransferase activity of Clostridium botulinum C3 exoenzyme

FEBS Letters

Morii, Narito¹  Ishizaki, Toshimasa¹  Watanabe, Naoki¹  Saito, Yuji¹  Narumiya, Shuh¹  Nemoto, Yasuo¹ 

[1] Department of Pharmacology, Kyoto University Faculty of Medicine, Yoshida, Sakyo-ku, Kyoto 606, Japan

关键词: Botulinum C3 exoenzyme;    ADP-ribosylation;    rho p21;    Swiss 3T3 cell;    rho-p21;    a small GTP-binding protein of the rho gene product;    GST-rho p21;    recombinant rho p21 fused to glutathione S-transferase;    C3 exoenzyme;    Clostridium botulinum C3 ADP-ribosyltransferase;    2-azidoNAD;    nicotinamide-2-azidoadenine dinucleotide;   

DOI  :  10.1016/0014-5793(95)00851-Y

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Clostridium botulinum C3 exoenzyme specifically ADP-ribosylates rho-p21 in eukaryotic cells. Trp¹⁸ and Glu¹⁷³ of this enzyme were substituted with other amino acids via site-directed mutagenesis. All substitutions at Glu¹⁷³ caused a significant reduction in affinity for NAD and diminished ADP-ribosyltransferase activity. On the other hand, the activity of enzymes with the substitution at Trp¹⁸ remained intact. Swiss 3T3 cells treated with the enzyme with the Trp¹⁸ substitution showed the typical morphologic changes of the C3 exoenzyme phenotype. In contrast, no changes were found in cells incubated with the Glu¹⁷³-substituted enzyme. These results indicate that the Glu¹⁷³ residue of the C3 exoenzyme plays a key role in interacting with NAD and in expression of ADP-ribosyltransferase activity, which is essential for the phenotypic change by C3 exoenzyme treatment.

【 授权许可】

Unknown