NMR Structure of the Myristylated Feline Immunodeficiency Virus Matrix Protein
NMR Structure of the Myristylated Feline Immunodeficiency Virus Matrix Protein
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DOI：
10.3390/v7052210
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发表时间：
2015-05-01
期刊：
影响因子：
4.7
通讯作者：
Summers, Michael F.
中科院分区：
文献类型：
--
作者：
Brown, Lola A.;Cox, Cassiah;Summers, Michael F.
人类免疫缺陷病毒（HIV -1型和-2型）Gag蛋白的膜靶向是由Gag的n端myristylated matrix （MA）结构域介导的，依赖于细胞磷脂酰肌醇4,5-二磷酸[PI(4,5)P-2]。为了确定其他慢病毒是否采用类似的膜靶向机制，我们启动了猫免疫缺陷病毒（FIV）的研究，这是一种广泛存在的猫科病原体，具有开发人类治疗药物的潜在用途。细菌共翻译肉豆芽形成是通过蛋白氨基端附近的两个氨基酸（Q5A/G6S; myrMA(Q5A/G6S)）突变而促进的。这些替换不影响病毒从转染细胞的组装或释放。核磁共振研究表明，肉豆蔻酰基被埋在疏水性口袋中，其结构类似于在肉豆蔻酰基化的HIV-1蛋白中观察到的。与最近发现的无花柱化FIV蛋白[myr(-)MA]的晶体结构比较表明，只需要对螺旋方向进行微小的改变就可以容纳被隔离的myr基团。从FIV感染的CRFK细胞的质膜上去除PI(4,5)P-2抑制了FIV颗粒的产生，这表明FIV像HIV一样劫持PI(4,5)P-2细胞信号系统，在病毒组装过程中指导细胞内Gag运输。
Membrane targeting by the Gag proteins of the human immunodeficiency viruses (HIV types-1 and -2) is mediated by Gag's N-terminally myristylated matrix (MA) domain and is dependent on cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5)P-2]. To determine if other lentiviruses employ a similar membrane targeting mechanism, we initiated studies of the feline immunodeficiency virus (FIV), a widespread feline pathogen with potential utility for development of human therapeutics. Bacterial co-translational myristylation was facilitated by mutation of two amino acids near the amino-terminus of the protein (Q5A/G6S; myrMA(Q5A/G6S)). These substitutions did not affect virus assembly or release from transfected cells. NMR studies revealed that the myristyl group is buried within a hydrophobic pocket in a manner that is structurally similar to that observed for the myristylated HIV-1 protein. Comparisons with a recent crystal structure of the unmyristylated FIV protein [myr(-)MA] indicate that only small changes in helix orientation are required to accommodate the sequestered myr group. Depletion of PI(4,5)P-2 from the plasma membrane of FIV-infected CRFK cells inhibited production of FIV particles, indicating that, like HIV, FIV hijacks the PI(4,5)P-2 cellular signaling system to direct intracellular Gag trafficking during virus assembly.