Crystal structure of the coat protein from the GA bacteriophage: model of the unassembled dimer.
Crystal structure of the coat protein from the GA bacteriophage: model of the unassembled dimer.
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GA 噬菌体外壳蛋白的晶体结构：未组装二聚体的模型。
DOI：
10.1002/pro.5560051211
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Ely,KR
中科院分区：
文献类型：
--
作者：
Ni,CZ;White,CA;Mitchell,RS;Wickersham,J;Kodandapani,R;Peabody,DS;Ely,KR
由于病毒外壳蛋白表面残基的差异，有四组 RNA 噬菌体具有不同的抗原和理化特性。外壳蛋白还在病毒生命周期中发挥翻译抑制蛋白的作用，与基因组内的 RNA 发夹结合。在这项研究中，报告了 II 组噬菌体 GA 外壳蛋白的第一个晶体结构，并与 I 组 MS2 外壳蛋白进行了比较。 GA 二聚体的结构以 2.8 Å 分辨率测定（R 因子 = 0.20）。外壳蛋白的整体折叠模式类似于完整病毒中的 I 组 MS2 外壳蛋白（Golmohammadi R、Valegård K、Fridborg K、Liljas L，1993，J Mol Biol 234：620-639）或未组装的二聚体（Ni CZ、Syed R、Kodandapani R、Wickersham J、Peabody DS、Ely KR， 1995，结构 3：255–263）。结构的不同之处在于 FG 环和 αA 螺旋的第一圈。 GA 和 MS2 外壳蛋白的序列在 129 个氨基酸残基中有 49 个不同。在完整病毒表面的 AB 和 FG 环中发现了导致蛋白质不同免疫学和物理特性的序列差异。位于跨二聚体界面的反向平行 β 折叠中的 RNA 结合位点内的潜在 RNA 接触残基有六个差异。三个差异涉及该凹面中心的残基； Lys/Arg 83、Ser/Asn 87 和 Asp/Glu 89。分子遗传学显示残基 87 通过 GA 或 MS2 外壳蛋白定义 RNA 结合特异性（Lim F、Spingola M、Peabody DS，1994，J Biol Chem 269：9006–9010）。这种序列差异反映了对这些外壳蛋白结合的翻译操纵子的不配对环中位置‐5处的核苷酸的识别。在 GA 中，该位置的核苷酸是嘌呤，而在 MS2 中，它是嘧啶。
There are four groups of RNA bacteriophages with distinct antigenic and physicochemical properties due to differences in surface residues of the viral coat proteins. Coat proteins also play a role as translational repressor during the viral life cycle, binding an RNA hairpin within the genome. In this study, the first crystal structure of the coat protein from a Group II phage GA is reported and compared to the Group I MS2 coat protein. The structure of the GA dimer was determined at 2.8 Å resolution (R‐factor = 0.20). The overall folding pattern of the coat protein is similar to the Group I MS2 coat protein in the intact virus (Golmohammadi R, Valegård K, Fridborg K, Liljas L, 1993,J Mol Biol 234:620–639) or as an unassembled dimer (Ni CZ, Syed R, Kodandapani R, Wickersham J, Peabody DS, Ely KR, 1995,Structure 3:255–263). The structures differ in the FG loops and in the first turn of the αA helix. GA and MS2 coat proteins differ in sequence at 49 of 129 amino acid residues. Sequence differences that contribute to distinct immunological and physical properties of the proteins are found at the surface of the intact virus in the AB and FG loops. There are six differences in potential RNA contact residues within the RNA‐binding site located in an antiparallel β‐sheet across the dimer interface. Three differences involve residues in the center of this concave site; Lys/Arg 83, Ser/Asn 87, and Asp/Glu 89. Residue 87 was shown by molecular genetics to define RNA‐binding specificity by GA or MS2 coat protein (Lim F, Spingola M, Peabody DS, 1994,J Biol Chem 269:9006–9010). This sequence difference reflects recognition of the nucleotide at position ‐5 in the unpaired loop of the translational operators bound by these coat proteins. In GA, the nucleotide at this position is a purine whereas in MS2, it is a pyrimidine.