What is the purpose of TcdB?
What is the purpose of TcdB?
The Transporter Classification Database (TCDB; tcdb.org) is a freely accessible reference resource, which provides functional, structural, mechanistic, medical and biotechnological information about transporters from organisms of all types.
What is TcdA and TcdB?
TcdA and TcdB are present in supernatant fluids of Clostridium difficile cultures and can be purified from filtrates. Both toxins are consistently detected in fecal samples from humans and animals and are now used as markers to diagnose C. difficile infection. Over 90% of patients infected with C.
What toxins does C Diff release?
Most C. difficile strains produce two major toxins, i.e., TcdA and TcdB, generated by the genes tcdA and tcdB within the organism’s Pathogenicity loci (PaLoc), while certain C.
What is TcdB toxin B?
Toxin B (TcdB) is a cytotoxin that has a molecular weight of 270 kDa and an isoelectric point, pl, of 4.1. Toxin B has four different structural domains: catalytic, cysteine protease, translocation, and receptor binding.
What is the difference between tcdA and TcdB?
A more recent experiment indicated that TcdB was, in fact, essential for virulence. Earlier research established TcdA strictly as an enterotoxin, and TcdB as a cytotoxin, but later both toxins were found to have the same mechanism of action.
What is a TcdA unique toxin variant?
A unique toxin variant is defined as a TcdA or TcdB open reading frame (ORF) that includes all four of the functional domains and whose amino acid sequence differs by at least one amino acid from any other entry. The most challenging region for collection of high-quality DNA sequence was in the C-terminal CROP domain]
What is the pathogenicity of Clostridium difficile TcdA?
The tcdA and tcdB genes are situated on the Clostridium difficile chromosome in a 19.6-kb pathogenicity locus (PaLoc) found only in toxigenic strains of C. difficile. Non toxigenic strains contain a 127 base pair fragment replacing the PaLoc.
What are the host cell receptors for TcdA?
Although there are currently no known host cell receptors for TcdA, three cell-surface receptors for TcdB have been identified: CSPG4, NECTIN3, and FZD1/2/7. The sites on TcdB that mediate binding to each receptor are not defined.
