Cooperative Role of Ubiquitin E2 and E3 in Streptococcus Mutans Dental Caries

Periodontal disease or periodontitis is a chronic inflammatory disease which involves a group interactions between the pathogen and cellular host response. It is found to be the most prevalent bacterial diseases in humans. Ubiquitination is the mechanism in which the polypeptide ubiquitin is covalently attached to the obsolete proteins and degrades them with the help of three enzymes namely E1 (ubiquitin-activating enzyme), E2 (Ubiquitinconjugating enzyme), and E3 (Ubiquitin ligase). Any misfolding or malfunction of these proteins results in the overall destability leading to metabolic disorders in humans. It was studied that some E3 enzymes help in activating the E2 enzymes. The study was aimed mainly to see the role of E2 in the ubiquitination process and to screen the expression levels in the absence of E3. In this study the protein of interest was extracted from the recombinant bacterial clones and purified using the affinity, ion exchange and gel exclusion chromatography. The protein was then studied for the ubiquitination and deubiquitination assays and confirmation was done using SDS PAGE. E3 is normally required for the substrate complex formation, but in contrast we found that in the absence of E3, conjugating activity was found. Our results showed that E2 alone was responsible for the polyubiquitination which was confirmed on the western blot in both the assays. This peculiar feature of E2 can unravel many questions of genetic disorders too in humans.