RNA-binding residues in the N-terminus of APOBEC3G influence its DNA sequence specificity and retrovirus restriction efficiency
RNA-binding residues in the N-terminus of APOBEC3G influence its DNA sequence specificity and retrovirus restriction efficiency
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DOI：
10.1016/j.virol.2015.04.019
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发表时间：
2015-09-01
期刊：
影响因子：
3.7
通讯作者：
Langlois, Marc-Andre
中科院分区：
文献类型：
--
作者：
Belanger, Kasandra;Langlois, Marc-Andre
APOBEC3G (A3G) 是一种宿主表达的蛋白质，可通过单链 DNA (ssDNA) 复制产物中胞嘧啶 (C) 到尿嘧啶 (U) 的诱变脱氨基作用来灭活逆转录病毒。 A3G 更喜欢在胞嘧啶 (5'CC) 之前对胞嘧啶进行脱氨基，而所有其他 A3 蛋白都以 5'TC 基序中的胞嘧啶为目标。结构和突变研究已将 A3G 的二核苷酸脱氨基偏好映射到该蛋白催化 C 末端结构域的环 7 中的残基。在这里，我们报道了 A3G 在其 N 末端具有双 W94A/W127A 取代，旨在消除 RNA 结合和蛋白质寡聚化，改变了酶对原病毒 DNA 的 DNA 脱氨特异性，从 5'CC 变为 5'TC。我们还表明，双重取代严重损害了其对 Vif 缺陷的 HIV-1 的脱氨酶和抗逆转录病毒活性。我们的结果强调，全长 A3G 蛋白的 N 端结构域对其 DNA 序列特异性和突变活性具有重要影响。 (C) 2015 Elsevier Inc. 保留所有权利。
APOBEC3G (A3G) is a host-expressed protein that inactivates retroviruses through the mutagenic deamination of cytosines (C) to uracils (U) in single-stranded DNA (ssDNA) replication products. A3G prefers to deaminate cytosines preceded by a cytosine (5'CC), whereas all other A3 proteins target cytosines in a 5'TC motifs. Structural and mutational studies have mapped the dinucleotide deamination preference of A3G to residues in loop 7 of the catalytic C-terminal domain of the protein. Here we report that A3G with a double W94A/W127A substitution in its N-terminus, designed to abolish RNA binding and protein oligomerization, alters the DNA deamination specificity of the enzyme from 5'CC to 5'TC on proviral DNA. We also show that the double substitution severely impairs its deaminase and antiretroviral activities on Vif-deficient HIV-1. Our results highlight that the N-terminal domain of the full length A3G protein has an important influence on its DNA sequence specificity and mutator activity. (C) 2015 Elsevier Inc. All rights reserved.