5j40 | pdb_00005j40
The X-ray structure of JCV Helicase
Structural highlights
FunctionLT_POVJC Isoform large T antigen is a key early protein essential for both driving viral replication and inducing cellular transformation. Plays a role in viral genome replication by driving entry of quiescent cells into the cell cycle and by autoregulating the synthesis of viral early mRNA. Displays highly oncogenic activities by corrupting the host cellular checkpoint mechanisms that guard cell division and the transcription, replication, and repair of DNA. Participates in the modulation of cellular gene expression preceeding viral DNA replication. This step involves binding to host key cell cycle regulators retinoblastoma protein RB1/pRb and TP53. Induces the disassembly of host E2F1 transcription factors from RB1, thus promoting transcriptional activation of E2F1-regulated S-phase genes. Inhibits host TP53 binding to DNA, abrogating the ability of TP53 to stimulate gene expression. Plays the role of a TFIID-associated factor (TAF) in transcription initiation for all three RNA polymerases, by stabilizing the TBP-TFIIA complex on promoters. Initiates viral DNA replication and unwinding via interactions with the viral origin of replication. Binds two adjacent sites in the SV40 origin. The replication fork movement is facilitated by Large T antigen helicase activity. Activates the transcription of viral late mRNA, through host TBP and TFIIA stabilization. Interferes with histone deacetylation mediated by HDAC1, leading to activation of transcription (By similarity). Publication Abstract from PubMedThere are currently no treatments for life-threatening infections caused by human polyomaviruses JCV and BKV. We therefore report herein the first crystal structure of the hexameric helicase of JCV large T antigen (apo) and its use to drive the structure-based design of dual JCV and BKV ATP-competitive inhibitors. The crystal structures obtained by soaking our early inhibitors into the JCV helicase allowed us to rapidly improve the biochemical activity of our inhibitors from 18 muM for the early 6-(2-methoxyphenyl)- and the 6-(2-ethoxyphenyl)-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazole hits 1a and 1b to 0.6 muM for triazolopyridine 12i. In addition, we were able to demonstrate measurable antiviral activity in Vero cells for our thiazolopyridine series in the absence of marked cytotoxicity, thus confirming the usefulness of this approach. Fragment-Based Discovery of Dual JC Virus and BK Virus Helicase Inhibitors.,Bonafoux D, Nanthakumar S, Bandarage UK, Memmott C, Lowe D, Aronov AM, Bhisetti GR, Bonanno KC, Coll J, Leeman J, Lepre CA, Lu F, Perola E, Rijnbrand R, Taylor WP, Wilson D, Zhou Y, Zwahlen J, Ter Haar E J Med Chem. 2016 Jul 20. PMID:27385654[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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