The primary structure of elongation factor G from Escherichia coli. A complete amino acid sequence.
The primary structure of elongation factor G from Escherichia coli. A complete amino acid sequence.
复制标题
大肠杆菌延伸因子 G 的一级结构。
DOI：
10.1016/0014-5793(82)80503-6
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发表时间：
1982
期刊：
影响因子：
3.5
通讯作者：
L. Vinokurov
中科院分区：
文献类型：
--
作者：
Ovchinnikov YuA;Alakhov YuB;Bundulis YuP;M. Bundule;N. V. Dovgas;V. P. Kozlov;L. P. Motuz;L. Vinokurov
伸长因子G （EF-G）是由一条含有mi - 80000的多肽链组成的大蛋白。用传统的方法来确定这种蛋白质的一级结构似乎不是最合理的。我们选择有限蛋白水解的方法作为研究的第一阶段，在许多情况下，将蛋白质分子切割成少量相对稳定的大片段，以抵抗蛋白酶的进一步影响。在轻度胰蛋白酶水解下，g因子被分成5个片段[1，参见2,3]，其中4个片段（T,-T,）形成完整的蛋白质多肽链（片段的命名和在蛋白质链中的排列见图1）。因此，通过对延伸因子G一级结构的研究，确定了这4个片段的结构，并寻找重叠的多肽来重建整个多肽链。由于TS-T片段分子量相对较低，对其结构的研究相对简单。n端片段T6的分子质量为6500，后续片段T的分子质量为7500，c端片段Ts的分子质量为25 000。传统的多肽链切割化学和酶的方法使我们能够较早地确定片段Tb [4]， T,[5,6]和Ts[7]的完整一级结构，共涉及> 350个氨基酸残基。为了阐明伸长因子G的完整结构，必须确定代表蛋白质分子中间部分的最大胰蛋白酶片段T4的氨基酸序列，并获得将所有有限胰蛋白酶溶解片段连接成1多肽链的肽。为此，研究了溴化氰裂解蛋白质的产物和有限酸性水解Asp-Pro键的产物。
Elongation factor G (EF-G) is a large protein consisting of one polypeptide chain with MI-80 000. Studies of this protein by traditional methods used to determine the primary structure did not seem the most rational. We chose the method of limited proteolysis as the first stage of studies permitting, in many cases, cleavage of the protein molecule into a small number of large fragments relatively stable against further effects of protease. On mild tryptic hydrolysis the G-factor is split into 5 fragments [1, cf. 2, 3], 4 of which (T,-T,) form the complete protein poly peptide chain (for fragment nomenclature and arrangement in the protein chain see fig. 1). Thus, the studies of the primary structure of the elongation factor G led to determination of the structure of these 4 fragments and a search for the overlapping peptides for reconstitution of the entire polypeptide chain. Studies of the structure of fragments TS-T, were relatively simple due to their comparatively low molecular mass. The molecular mass of the N-terminal fragment T6 is 6500, that of the following fragment T,, 7500, and that of the C-terminal fragment Ts, 25 000. Traditional chemical and enzymatic methods of polypeptide chain cleavage permitted us earlier to determine the complete primary structures of fragments Tb [4], T,[5, 6] and Ts [7] involving a total of> 350 amino acid residues. To elucidate the complete structure of elongation factor G it was necessary to determine the ammo acid sequence of the largest tryptic fragment T4 representing the middle part of the protein molecule and to obtain the peptides joining all the fragments of limited trypsinolysis into a 1 polypeptide chain. To this end, the products of protein cleavage by cyanogen bromide and those of limited acidic hydrolysis at the Asp-Pro bond were studied.