Modeling and structure function analysis of the putative anchor site of yeast telomerase.

TitleModeling and structure function analysis of the putative anchor site of yeast telomerase.
Publication TypeJournal Article
Year of Publication2007
AuthorsLue NF, Li Z
JournalNucleic Acids Res
Date Published2007
KeywordsAnimals, Models, Molecular, Mutagenesis, Site-Directed, Protein Structure, Tertiary, RNA, Saccharomyces cerevisiae Proteins, Static Electricity, Structural Homology, Protein, Structure-Activity Relationship, Telomerase, Telomere, Tetrahymena

Telomerase is a ribonucleoprotein reverse transcriptase responsible for extending one strand of the telomere terminal repeats. Unique among reverse transcriptases, telomerase is thought to possess a DNA-binding domain (known as anchor site) that allows the enzyme to add telomere repeats processively. Previous crosslinking and mutagenesis studies have mapped the anchor site to an N-terminal region of TERT, and the structure of this region of Tetrahymena TERT was recently determined at atomic resolutions. Here we use a combination of homology modeling, electrostatic calculation and site-specific mutagenesis analysis to identify a positively charged, functionally important surface patch on yeast TERT. This patch is lined by both conserved and non-conserved residues, which when mutated, caused loss of telomerase processivity in vitro and telomere shortening in vivo. In addition, we demonstrate that a point mutation in this domain of yeast TERT simultaneously enhanced the repeat addition processivity of telomerase and caused telomere elongation. Our data argue that telomerase anchor site has evolved species-specific residues to interact with species-specific telomere repeats. The data also reinforce the importance of telomerase processivity in regulating telomere length.

Alternate JournalNucleic Acids Res
PubMed ID17670795
PubMed Central IDPMC1976438
Grant ListR01 GM062631 / GM / NIGMS NIH HHS / United States
GM62631 / GM / NIGMS NIH HHS / United States

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