Distribution of reversing factor in reticulocyte lysates during active protein synthesis and on inhibition by heme deprivation or double-stranded RNA.
Distribution of reversing factor in reticulocyte lysates during active protein synthesis and on inhibition by heme deprivation or double-stranded RNA.
复制标题
活性蛋白合成过程中以及血红素剥夺或双链 RNA 抑制过程中网织红细胞裂解物中逆转因子的分布。
DOI：
10.1073/pnas.81.22.6998
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发表时间：
1984
影响因子：
11.1
通讯作者：
London,IM
中科院分区：
文献类型：
--
作者：
Thomas,NS;Matts,RL;Petryshyn,R;London,IM
我们最近发现，蛋白质合成活性与逆转因子 (RF) 的功能之间存在直接相关性，RF 是正常条件下全网织红细胞裂解物中 GDP-GTP 交换的催化剂，以及血红素缺乏、双链 RNA 或氧化型谷胱甘肽对蛋白质合成的抑制。在本文中，我们报告称，在受血红素剥夺或双链 RNA 抑制的全裂解物中，RF 可作为一种非核糖体复合物进行检测，其 α 亚基 [eIF-2(alpha P)] 被磷酸化。该复合物不含未磷酸化的 eIF-2 α，并且存在的 GDP 可自由解离。所有非核糖体 eIF-2(alpha P) 在完全抑制的裂解物中与 RF 复合；我们尚未检测到游离的 eIF-2(alpha P)。该 [RF X eIF-2(alpha P)] 复合物中的 RF 无法催化 eIF-2-GDP 中 GDP 的释放。非核糖体部分中存在的 eIF-2(α P) 去磷酸化会释放活性 RF，从而能够执行其正常的鸟嘌呤核苷酸交换功能。
We have recently shown a direct correlation between protein synthetic activity and the function of reversing factor (RF) as a catalyst of GDP-GTP exchange in whole reticulocyte lysates under normal conditions and on inhibition of protein synthesis by heme deficiency, double-stranded RNA, or oxidized glutathione. In this paper we report that RF is detectable as a nonribosomal complex with eukaryotic initiation factor 2 phosphorylated in its alpha subunit [eIF-2(alpha P)] in whole lysates inhibited by heme deprivation or by double-stranded RNA. The complex contains no unphosphorylated eIF-2 alpha, and the GDP present is freely dissociable. All nonribosomal eIF-2(alpha P) is complexed with RF in fully inhibited lysates; we have not detected free eIF-2(alpha P). RF in this [RF X eIF-2(alpha P)] complex is unavailable to catalyze the release of GDP from eIF-2-GDP. Dephosphorylation of eIF-2(alpha P) present in nonribosomal fractions releases active RF, which is able to carry out its normal guanine nucleotide exchange function.