» Articles » PMID: 20852643

Structural Basis of HIV-1 Resistance to AZT by Excision

Abstract

Human immunodeficiency virus (HIV-1) develops resistance to 3'-azido-2',3'-deoxythymidine (AZT, zidovudine) by acquiring mutations in reverse transcriptase that enhance the ATP-mediated excision of AZT monophosphate from the 3' end of the primer. The excision reaction occurs at the dNTP-binding site, uses ATP as a pyrophosphate donor, unblocks the primer terminus and allows reverse transcriptase to continue viral DNA synthesis. The excision product is AZT adenosine dinucleoside tetraphosphate (AZTppppA). We determined five crystal structures: wild-type reverse transcriptase-double-stranded DNA (RT-dsDNA)-AZTppppA; AZT-resistant (AZTr; M41L D67N K70R T215Y K219Q) RT-dsDNA-AZTppppA; AZTr RT-dsDNA terminated with AZT at dNTP- and primer-binding sites; and AZTr apo reverse transcriptase. The AMP part of AZTppppA bound differently to wild-type and AZTr reverse transcriptases, whereas the AZT triphosphate part bound the two enzymes similarly. Thus, the resistance mutations create a high-affinity ATP-binding site. The structure of the site provides an opportunity to design inhibitors of AZT-monophosphate excision.

Citing Articles

Kinetic coevolutionary models predict the temporal emergence of HIV-1 resistance mutations under drug selection pressure.

Biswas A, Choudhuri I, Arnold E, Lyumkis D, Haldane A, Levy R Proc Natl Acad Sci U S A. 2024; 121(15):e2316662121.

PMID: 38557187 PMC: 11009627. DOI: 10.1073/pnas.2316662121.


Evolution of drug resistance drives destabilization of flap region dynamics in HIV-1 protease.

Rajendran M, Ferran M, Mouli L, Babbitt G, Lynch M Biophys Rep (N Y). 2023; 3(3):100121.

PMID: 37662576 PMC: 10469570. DOI: 10.1016/j.bpr.2023.100121.


Human endogenous retrovirus-K (HERV-K) reverse transcriptase (RT) structure and biochemistry reveals remarkable similarities to HIV-1 RT and opportunities for HERV-K-specific inhibition.

Baldwin E, Gotte M, Tchesnokov E, Arnold E, Hagel M, Nichols C Proc Natl Acad Sci U S A. 2022; 119(27):e2200260119.

PMID: 35771941 PMC: 9271190. DOI: 10.1073/pnas.2200260119.


Insights into HIV-1 Reverse Transcriptase (RT) Inhibition and Drug Resistance from Thirty Years of Structural Studies.

Singh A, Das K Viruses. 2022; 14(5).

PMID: 35632767 PMC: 9148108. DOI: 10.3390/v14051027.


Sampling of Protein Conformational Space Using Hybrid Simulations: A Critical Assessment of Recent Methods.

Kaynak B, Krieger J, Dudas B, Dahmani Z, Costa M, Balog E Front Mol Biosci. 2022; 9:832847.

PMID: 35187088 PMC: 8855042. DOI: 10.3389/fmolb.2022.832847.


References
1.
Krebs R, Immendorfer U, Thrall S, Wohrl B, Goody R . Single-step kinetics of HIV-1 reverse transcriptase mutants responsible for virus resistance to nucleoside inhibitors zidovudine and 3-TC. Biochemistry. 1997; 36(33):10292-300. DOI: 10.1021/bi970512z. View

2.
Brunger A, Adams P, Clore G, DeLano W, Gros P, Grosse-Kunstleve R . Crystallography & NMR system: A new software suite for macromolecular structure determination. Acta Crystallogr D Biol Crystallogr. 1998; 54(Pt 5):905-21. DOI: 10.1107/s0907444998003254. View

3.
Dharmasena S, Pongracz Z, Arnold E, Sarafianos S, Parniak M . 3'-Azido-3'-deoxythymidine-(5')-tetraphospho-(5')-adenosine, the product of ATP-mediated excision of chain-terminating AZTMP, is a potent chain-terminating substrate for HIV-1 reverse transcriptase. Biochemistry. 2007; 46(3):828-36. DOI: 10.1021/bi061364s. View

4.
Yahi N, Tamalet C, Tourres C, Tivoli N, Ariasi F, Volot F . Mutation patterns of the reverse transcriptase and protease genes in human immunodeficiency virus type 1-infected patients undergoing combination therapy: survey of 787 sequences. J Clin Microbiol. 1999; 37(12):4099-106. PMC: 85889. DOI: 10.1128/JCM.37.12.4099-4106.1999. View

5.
White K, Chen J, Feng J, Margot N, Ly J, Ray A . The K65R reverse transcriptase mutation in HIV-1 reverses the excision phenotype of zidovudine resistance mutations. Antivir Ther. 2006; 11(2):155-63. DOI: 10.1177/135965350601100209. View