Biotinylation of yeast histones and its characteristics

Biotinylation is a posttranslational modification that has an important role in the covalent binding of biotin to lysine residues of protein aided by biotin protein ligase (Bpl1p). Biotin is important for fatty acid metabolism and cell growth. Biotin is used as a cofactor for carboxylase such as pyruvate carboxylase and acetyl-CoA carboxylase. The biotinylated lysine residue is almost invariably located in a consensus sequence, AMKM, within carboxylases. As a result, biotinylation can occur across widely divergent organisms. Additionally, the histones H2A, H2B and H4 of Candida albicans lack a consensus sequence, but can be biotinylated by native C. albicans Bpl1p in vivo which is biotinylated in non-site-specific proteins. In this research, we used in vivo and in vitro experiments and analysis by SDS-PAGE and Western blotting. The results show that the biotinylation of H2B is temperature and biotin concentration dependent. Moreover, the Bpl1p of C. albicans failed to biotinylate other yeast histone proteins (Saccharomyces cerevisiae) in vivo and in vitro. Future studies are underway to analyze the specificity and mechanism of biotinylation by C. albicans Bpl1p.