Phosphorylation and functionality of CdtR in Clostridium difficile.

In this study, we generated R20291ΔPalocΔcdtR model strains expressing CdtR phospho-variants in which our predicted phospho-accepting Asp, Asp61 was mutated for Ala or Glu. The constructs were assessed for their ability to restore CDT production. Dephospho-CdtR-Asp61Ala was completely non-functional and mirrored the cdtR-deletion mutant, whilst phospho-CdtR-Asp61Glu was functional, possessing 38-52% of wild-type activity. Taken together, these data suggest that CdtR is activated by phosphorylation of Asp61. The same principles were applied to assess the function of ribotype 078-derived CdtR, which was shown to be non-functional owing to polymorphisms present within its coding gene. Conversely, polymorphisms present within its promoter region, provide significantly enhanced promoter activity compared with its ribotype 027 counterpart. To ensure our data were representative for each ribotype, we determined that the cdtR nucleotide sequence was conserved in a small library of eight ribotype 027 clinical isolates and nineteen ribotype 078 isolates from clinical and animal origin. PMID: 31323291 [PubMed - as supplied by publisher]
Source: Anaerobe - Category: Microbiology Authors: Tags: Anaerobe Source Type: research