SINGLE CHARGE CHANGE ON THE HELICAL SURFACE OF THE PARAMYOSIN ROD DRAMATICALLY DISRUPTS THICK FILAMENT ASSEMBLY IN CAENORHABDITIS-ELEGANS
SINGLE CHARGE CHANGE ON THE HELICAL SURFACE OF THE PARAMYOSIN ROD DRAMATICALLY DISRUPTS THICK FILAMENT ASSEMBLY IN CAENORHABDITIS-ELEGANS
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DOI：
10.1016/0022-2836(91)90184-8
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发表时间：
1991-06-05
影响因子：
5.6
通讯作者：
KAGAWA, H
中科院分区：
文献类型：
--
作者：
GENGYOANDO, K;KAGAWA, H
α-螺旋卷曲螺旋蛋白质之间的电荷相互作用已经被假定为决定许多丝状蛋白质的排列，如肌球蛋白重链杆、副肌球蛋白和α-角蛋白。本文测定了秀丽隐杆线虫unc 15副肌球蛋白基因9个突变的序列变化，包括1个无义突变、4个错义突变、1个缺失突变和3个抑制突变。这些突变位点位于一个分子模型上，通过优化副肌球蛋白杆之间的电荷相互作用构建。值得注意的是，单电荷反转（例如，谷氨酸到赖氨酸），在体内破坏或恢复纤维的组装。副肌球蛋白分子内的突变的位置支持副肌球蛋白组装的模型，并进一步表明，C-末端区域包含一个簇的5个突变，和一个网站与它相互作用，在组装中发挥关键作用。在该C-末端区域中的一个氨基酸取代，其中存在“弱点”，导致与一种单克隆抗副肌球蛋白抗体的反应性丧失。结果表明，一个单一的氨基酸取代可以改变α-螺旋分子的组装特性。
Charge interactions between α-helical coiled-coil proteins have been postulated to determine the alignment of many filamentous proteins, such as myosin heavy-chain rod, paramyosin and α-keratin. Here we determined the sequence changes in nine mutations in theunc-15 paramyosin gene of Caenorhabditis elegans, including one nonsense, four missense, one deletion and three suppressor mutations. These mutation sites were located on a molecular model, constructed by optimizing charge interactions between paramyosin rods. Remarkably, single charge reversals (e.g., glutamic acid to lysine) were found that either disrupted or restored filament assemblyin vivo. The positions of the mutations within the paramyosin molecule support the models of paramyosin assembly and further suggest that the C-terminal region containing a cluster of five mutations, and a site interacting with it, play a key role in assembly. One amino acid substitution in this C-terminal region, in which there is a “weak spot”, led to a loss of reactivity with one monoclonal anti-paramyosin antibody. The results demonstrate how a single amino acid substitution can alter the assembly properties of α-helical molecules.