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2dok
From Proteopedia
Crystal structure of the PIN domain of human EST1A
Structural highlights
Function[EST1A_HUMAN] Component of the telomerase ribonucleoprotein (RNP) complex that is essential for the replication of chromosome termini. May have a general role in telomere regulation. Promotes in vitro the ability of TERT to elongate telomeres. Overexpression induces telomere uncapping, chromosomal end-to-end fusions (telomeric DNA persists at the fusion points) and did not perturb TRF2 telomeric localization. Binds to the single-stranded 5'-(GTGTGG)(4)GTGT-3' telomeric DNA, but not to a telomerase RNA template component (TER).[1] [2] [3] [4] [5] Plays a role in nonsense-mediated mRNA decay. Is thought to provide a link to the mRNA degradation machinery as it has endonuclease activity required to initiate NMD, and to serve as an adapter for UPF1 to protein phosphatase 2A (PP2A), thereby triggering UPF1 dephosphorylation. Degrades single-stranded RNA (ssRNA), but not ssDNA or dsRNA.[6] [7] [8] [9] [10] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSaccharomyces cerevisiae Est1p is a telomerase-associated protein essential for telomere length homeostasis. hEST1A is one of the three human Est1p homologues and is considered to be involved not only in regulation of telomere elongation or capping but also in nonsense-mediated degradation of RNA. hEST1A is composed of two conserved regions, Est1p homology and PIN (PilT N-terminus) domains. The present study shows the crystal structure of the PIN domain at 1.8 A resolution. The overall structure is composed of an alpha/beta fold or a core structure similar to the counterpart of 5' nucleases and an extended structure absent from archaeal PIN-domain proteins and 5' nucleases. The structural properties of the PIN domain indicate its putative active center consisting of invariant acidic amino acid residues, which is geometrically similar to the active center of 5' nucleases and an archaeal PAE2754 PIN-domain protein associated with exonuclease activity. Crystal structure of the PIN domain of human telomerase-associated protein EST1A.,Takeshita D, Zenno S, Lee WC, Saigo K, Tanokura M Proteins. 2007 Sep 1;68(4):980-9. PMID:17557331[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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