The glutamine side chain at position 91 on the β5a-β5b loop of human immunodeficiency virus type 1 reverse transcriptase is required for stabilizing the dNTP binding pocket.
The glutamine side chain at position 91 on the β5a-β5b loop of human immunodeficiency virus type 1 reverse transcriptase is required for stabilizing the dNTP binding pocket.
复制标题
人类免疫缺陷病毒 1 型逆转录酶 β5a-β5b 环上位置 91 的谷氨酰胺侧链是稳定 dNTP 结合袋所必需的。
DOI：
10.1021/bi200815e
复制
发表时间：
2011
期刊：
影响因子：
2.9
通讯作者：
Pandey,VirendraN
中科院分区：
文献类型：
--
作者：
Pandey,Nootan;Mishra,ChaturbhujA;Manvar,Dinesh;Upadhyay,AlokK;Talele,TanajiT;Comollo,ThomasW;Kaushik-Basu,Neerja;Pandey,VirendraN
Earlier, we postulated that Gln91 of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) stabilizes the side chain of Tyr183 via hydrogen bonding interaction between O(H) of Tyr183 and CO of Q91 [Harris, D., et al. (1998)Biochemistry 37, 9630–9640]. To test this hypothesis, we generated mutant derivatives of Gln91 and analyzed their biochemical properties. The efficiency of reverse transcription was severely impaired by nonconservative substitution of Gln with Ala, while conservative substitution of Gln with Asn resulted in an approximately 70% loss of activity, a value similar to that observed with the Y183F mutation. The loss of polymerase activity from both Q91A and Q91N was significantly improved by a Met to Val substitution at position 184. Curiously, the Q91N mutant exhibited stringency in discriminating between correct and incorrect nucleotides, suggesting its possible interaction with residues influencing the flexibility of the dNTP binding pocket. In contrast, both double mutants, Q91A/M184V and Q91N/M184V, are found to be as error prone as the wild-type enzyme. We propose a model that suggests that subtle structural changes in the region due to mutation at position 91 may influence the stability of the side chain of Tyr183 in the catalytic YMDD motif of the enzyme, thus altering the active site geometry that may interfere in substrate recognition.
