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Publication Abstract from PubMed

Hepatitis B virus (HBV) reverse transcriptase (RT) is essential for viral replication and is an important drug target. Nonetheless, the notorious insolubility of HBV RT has hindered experimental structural studies and structure-based drug design. Here, we demonstrate that a Q151M substitution alone at the nucleotide-binding site (N-site) of human immunodeficiency virus type-1 (HIV-1) RT renders HIV-1 highly sensitive to entecavir (ETV), a potent nucleoside analogue RT inhibitor (NRTI) against HBV. The results suggest that Met151 forms a transient hydrophobic interaction with the cyclopentyl methylene of ETV, a characteristic hydrophobic moiety of ETV. We thus solved the crystal structures of HIV-1 RT(Q151M):DNA complex with bound dGTP or ETV-triphosphate (ETV-TP). The structures revealed that ETV-TP is accommodated at the N-site slightly apart from the ribose ring of the 3'-end nucleotide, compared to the position of bound dGTP and previously reported NRTI/dNTP. In addition, the protruding methylene group of bound ETV-TP directly pushes the side-chain of Met184 backward. Met184 is a key residue that confers ETV resistance upon substitution with smaller Ile/Val. These results provide novel insights into NRTI binding to the N-site and further provide important clues for the development of novel anti-HBV/HIV-1 RT inhibitors to overcome critical drug resistance.

HIV-1 with HBV-associated Q151M substitution in RT becomes highly susceptible to entecavir: structural insights into HBV-RT inhibition by entecavir.,Yasutake Y, Hattori SI, Hayashi H, Matsuda K, Tamura N, Kohgo S, Maeda K, Mitsuya H Sci Rep. 2018 Jan 26;8(1):1624. doi: 10.1038/s41598-018-19602-9. PMID:29374261^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.