5dfn
From Proteopedia
Structure of Tetrahymena Telomerase P45 C-terminal domain
Structural highlights
FunctionTAP45_TETTS Component of a CST-like subcomplex of the holoenzyme telomerase ribonucleoprotein complex, which stimulates telomerase complementary-strand synthesis (PubMed:26551074). Telomerase is an essential ribonucleoprotein enzyme that copies new telomeric repeats onto chromosome ends by repetitively synthesizing the short telomere-repeat sequence 5'-TTGGGG-3' using an RNA template component TER (PubMed:26551074). The CST-like subcomplex (also named 7-4-1) binds telomeric single-stranded DNA and coordinates telomere G-strand and C-strand synthesis (PubMed:26551074).[1] Publication Abstract from PubMedTelomerase helps maintain telomeres by processive synthesis of telomere repeat DNA at their 3'-ends, using an integral telomerase RNA (TER) and telomerase reverse transcriptase (TERT). We report the cryo-electron microscopy structure of Tetrahymena telomerase at ~9 angstrom resolution. In addition to seven known holoenzyme proteins, we identify two additional proteins that form a complex (TEB) with single-stranded telomere DNA-binding protein Teb1, paralogous to heterotrimeric replication protein A (RPA). The p75-p45-p19 subcomplex is identified as another RPA-related complex, CST (CTC1-STN1-TEN1). This study reveals the paths of TER in the TERT-TER-p65 catalytic core and single-stranded DNA exit; extensive subunit interactions of the TERT essential N-terminal domain, p50, and TEB; and other subunit identities and structures, including p19 and p45C crystal structures. Our findings provide structural and mechanistic insights into telomerase holoenzyme function. Structure of Tetrahymena telomerase reveals previously unknown subunits, functions, and interactions.,Jiang J, Chan H, Cash DD, Miracco EJ, Ogorzalek Loo RR, Upton HE, Cascio D, O'Brien Johnson R, Collins K, Loo JA, Zhou ZH, Feigon J Science. 2015 Oct 30;350(6260):aab4070. doi: 10.1126/science.aab4070. Epub 2015, Oct 15. PMID:26472759[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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