Yeast telomerase protein Est3 is a novel type of GTPase

Telomerase is a key participant of telomere length maintaining system in the majority of eukaryotes. It synthesizes telomere repeats at the 3′-end of telomere DNA using its own RNA template. The Saccharomyces cerevisiae telomerase complex contains the reverse transcriptase (Est2) and RNA subunits (TLC1), as well as number of additional proteins among which Est3 is known to be essential for telomere length maintenance. We have found that Est3 can hydrolyze GTP in vitro and investigated parameters of this reaction. The data obtained suggest that Est3 may function as unusual GTPase in vivo.