Biotinylation of histones by a yeast biotin protein ligase

• Main Authors: Arief Muammar, 孟恩立
• Other Authors: Chien-Chia Wang
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/17954537057253487900

碩士 === 國立中央大學 === 生命科學系 === 104 === Histones H1, H2A, H2B, H3 and H4 are DNA-binding proteins that mediate the folding of DNA into chromatin. Various posttranslational modifications of histones such as phosphorylation, acetylation, ubiquitinylation and ADP-ribosylation regulate processes such as transcription, replication and repair of DNA. One of the posttranslational modifications is biotinylation, which is covalent binding of biotin to lysine residues of a protein, mediated by biotin protein ligase (Bpl1p). Biotin is required for cell growth and fatty acid metabolism. It is used as a cofactor for carboxylases such as acetyl-CoA carboxylase and pyruvate carboxylase. The biotinylated lysine residue is almost invariably positioned in a consensus sequence, AMKM, within carboxylases. As a result, biotinylation can occur across widely divergent species. Paradoxically, the histones H2A, H2B and H4 of Candida albican lack a consensus sequence, but can be bioyinylated by its own biotin protein ligase (Bpl1p) in vivo. In addition, biotinylation of these histone proteins is non site specific. In this study, we showed that biotinylation of H2B is biotin concentration dependent and temperature dependent. Moreover, the Bpl1p of C. albicans failed to biotinylate the histone proteins of Saccharomyces cereviseae in vivo and in vitro. More studies are underway to elucidate the specificity and mechanism of biotinylation by C. albican Bpl1p.