TY - JOUR
T1 - Altered strand transfer activity of a multiple-drug-resistant human immunodeficiency virus type 1 reverse transcriptase mutant with a dipeptide fingers domain insertion
AU - Nguyen, Laura A.
AU - Daddacha, Waaqo
AU - Rigby, Sean
AU - Bambara, Robert A.
AU - Kim, Baek
N1 - Funding Information:
This study was supported by National Institutes of Health grants AI049781 (B.K.) and GM049573 (R.A.B.).
PY - 2012/1/13
Y1 - 2012/1/13
N2 - Prolonged highly active anti-retroviral therapy with multiple nucleoside reverse transcriptase inhibitors for the treatment of patients infected with human immunodeficiency virus type 1 (HIV-1) can induce the development of an HIV-1 reverse transcriptase (RT) harboring a dipeptide insertion at the RT fingers domain with a background thymidine analog mutation. This mutation renders viral resistance to multiple nucleoside reverse transcriptase inhibitors. We investigated the effect of the dipeptide fingers domain insertion mutation on strand transfer activity using two clinical RT variants isolated during the pre-treatment and post-treatment of an infected patient, termed pre-drug RT without dipeptide insertion and post-drug RT with Ser-Gly insertion, respectively. First, the post-drug RT displayed elevated strand transfer activity compared to the pre-drug RT, with two different RNA templates. Second, the post-drug RT exhibited less RNA template degradation than the pre-drug RT but higher polymerization-dependent RNase H activity. Third, the post-drug RT had a faster association rate (kon) for template binding and a lower equilibrium binding constant Kd for the template, leading to a template binding affinity tighter than that of the pre-drug RT. The k off values for the pre-drug RT and the post-drug RT were similar. Finally, the removal of the dipeptide insertion from the post-drug RT abolished the elevated strand transfer activity and RNase H activity, in addition to the loss of azidothymidine resistance. These biochemical data suggest that the dipeptide insertion elevates strand transfer activity by increasing the interaction of the RT with the RNA donor template, promoting cleavage that generates more invasion sites for the acceptor template during DNA synthesis.
AB - Prolonged highly active anti-retroviral therapy with multiple nucleoside reverse transcriptase inhibitors for the treatment of patients infected with human immunodeficiency virus type 1 (HIV-1) can induce the development of an HIV-1 reverse transcriptase (RT) harboring a dipeptide insertion at the RT fingers domain with a background thymidine analog mutation. This mutation renders viral resistance to multiple nucleoside reverse transcriptase inhibitors. We investigated the effect of the dipeptide fingers domain insertion mutation on strand transfer activity using two clinical RT variants isolated during the pre-treatment and post-treatment of an infected patient, termed pre-drug RT without dipeptide insertion and post-drug RT with Ser-Gly insertion, respectively. First, the post-drug RT displayed elevated strand transfer activity compared to the pre-drug RT, with two different RNA templates. Second, the post-drug RT exhibited less RNA template degradation than the pre-drug RT but higher polymerization-dependent RNase H activity. Third, the post-drug RT had a faster association rate (kon) for template binding and a lower equilibrium binding constant Kd for the template, leading to a template binding affinity tighter than that of the pre-drug RT. The k off values for the pre-drug RT and the post-drug RT were similar. Finally, the removal of the dipeptide insertion from the post-drug RT abolished the elevated strand transfer activity and RNase H activity, in addition to the loss of azidothymidine resistance. These biochemical data suggest that the dipeptide insertion elevates strand transfer activity by increasing the interaction of the RT with the RNA donor template, promoting cleavage that generates more invasion sites for the acceptor template during DNA synthesis.
KW - HIV-1
KW - fingers domain insertion
KW - multiple drug resistance
KW - reverse transcriptase
KW - strand transfer
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U2 - 10.1016/j.jmb.2011.11.014
DO - 10.1016/j.jmb.2011.11.014
M3 - Article
C2 - 22100453
AN - SCOPUS:84855797551
SN - 0022-2836
VL - 415
SP - 248
EP - 262
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 2
ER -