Telomerase Complex from Yeast Saccharomyces cerevisiae Contains a Biotinylated Component

Telomerase adds telomeric repeats to single-stranded DNA at the ends of the chromosomes. This enzyme is a ribonucleoprotein complex. Telomerase from yeast Saccharomyces cerevisiae consists of TLC1 RNA, which serves as a template for the synthesis of telomeric repeats, telomerase reverse transcriptase Est 2p, and a number of accessory proteins (Est 1p, Est 3p, Ku70/Ku80, and Sm-complex). We found that the yeast telomerase complex contains a biotinylated component. The telomerase fraction containing biotinylated protein is active in vitro and constitutes a small part of the total amount of active telomerase isolated from cells. We speculate about the nature of the biotinylated component.