TABLE 8.
Substrate specificity of LCT glycosyltransferase domainsa
| LCT | Sugar donor(s) | Transfer(s) | Strain | Target(s) |
|---|---|---|---|---|
| TcdA | UDP-glucose (220) | Glucose | VPI 10463 (A1) | RhoA/B/C, Rac1, RhoG, Cdc42, Rap1/2, H/K/N-Ras (277, 278) |
| C34 | Rho, Rac, Cdc42, Rap (279) | |||
| TcdB | UDP-glucose (220) | Glucose | VPI 10463 (B1) | RhoA/B/C, Rac1/2/3, Cdc42, RhoG (177, 277, 278, 280) |
| RT027 (B2) | RhoA/B, Rac1/2/3, Cdc42, Rap1A/2A, R-Ras (177, 277, 281) | |||
| 1470 (B3) | Rac, Cdc42, Rap, Ral, R-Ras (282) | |||
| 8864 (B4) | Rac, Cdc42, Rap, Ral, R-Ras (279, 283) | |||
| C34 (B7)b | Rho, Rac, Cdc42, Rap, Ral, R-Ras (279) | |||
| RT019 (B7) | Rac1/2/3, Cdc42, Rap2A/1B, R-Ras1/2, (H/K)-Ras (177, 281) | |||
| HMX-152 (B7) | RhoA (110) | |||
| HSJD-312 (B7) | RhoA (110) | |||
| HMX-149 (B11) | RhoA (110) | |||
| TcsL | UDP-glucose (221) | Glucose | VPI 9048 | Rac, Cdc42, Rap, Ras (221, 284) |
| IP 82 | Rac, Rap, Ral, Ras (221, 285) | |||
| 6018 | Rac1, RhoG, Rap1/2, Ral, (H/K/N)-Ras (277, 284) | |||
| TcsH | UDP-glucosec (221) | Glucose | VPI 9048 | Rho, Rac, Cdc42, Ras (221, 286) |
| TcnA | UDP-GlcNAc (222) | N-Acetylglucosamine | 590, 19402 | Rho, Rac, Cdc42 (221, 287) |
| TpeL | UDP-glucose, UDP-GlcNAcd (189, 223) | Glucose, N-acetylglucosamine | MC18 | Rac, Rap, Ral, Ras (223) |
| JGS1495 | (H/K/N)-Ras (288) |
aThis table is based in part on data from Chandrasekaran and Lacy (239). If the sequence of the C. difficile subtype was available, the TcdA or TcdB subtype is indicated in parentheses. Subtyping based on that reported by Mansfield et al. (138).
bBased on partial sequencing of the toxin gene.
cBased on conservation of key UDP-glucose binding features.
dPreferentially modifies GTPases by GlcNAcylation using UDP-GlcNAc (189).