SNAP output for PDB entry 5xn1 [SNAP web server]

PDB-id

5xn1; SNAP-derived features in text and JSON formats; DNAproDB

Class

transferase-DNA

Method

X-ray (2.446 Å)

Summary

Hiv-1 reverse transcriptase q151m:DNA:entecavir-triphosphate ternary complex

Reference

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

Abstract

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 RTQ151M: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.