Properties of a membrane-attached form of the folded chromosome of Escherichia coli.
Properties of a membrane-attached form of the folded chromosome of Escherichia coli.
复制标题
大肠杆菌折叠染色体膜附着形式的特性。
DOI：
10.1016/0022-2836(74)90576-2
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发表时间：
1974
影响因子：
5.6
通讯作者：
E. Burgi
中科院分区：
文献类型：
--
作者：
A. Worcel;E. Burgi
用非离子去污剂在 1.-0m-NaCl 中温和裂解后，溶菌酶产生的大肠杆菌会释放出两种类型的含 DNA 颗粒。 25 °C 裂解释放折叠染色体（1300 S 至 2200 S 颗粒）。 10 °C 下的裂解会产生更快的沉淀结构（3000 S 至 4000 S）。两种类型的颗粒共存于中间温度（即 15 °C）裂解细胞的提取物中。3000 个 S 至 4000 个 S 颗粒是附着在膜碎片上的折叠染色体；除了折叠的 DNA 和新生的 RNA 链外，它们还含有膜蛋白和磷脂。将膜附着的染色体与 1% Sarkosyl 一起孵育，释放折叠的染色体；这种肌酰基处理去除了膜蛋白和磷脂，并使颗粒的沉降速度减半，但对折叠的 DNA 和新生 RNA 链没有影响。膜附着的染色体无法从已完成 DNA 复制轮次的氨基酸饥饿细胞中分离出来；然后所有的 DNA 都以释放的折叠染色体的形式出现。蛋白质合成恢复后，染色体附着在膜上，然后 DNA 复制开始。对照强烈表明观察到的变化，即折叠染色体膜的附着和释放，与 DNA 复制本身的行为有关。
Two types of DNA-containing particles are released from lysozyme-producedEscherichia colispheroplasts after gentle lysis with non-ionic detergents in 1.-0m-NaCl. Lysis at 25 °C releases the folded chromosomes (1300 S to 2200 S particles). Lysis at 10 °C results in faster sedimenting structures (3000 S to 4000 S). Both types of particles coexist in extracts of cells lysed at intermediate temperatures, i.e. 15 °C.The 3000 S to 4000 S particles are folded chromosomes attached to membrane fragments; they contain membrane proteins and phospholipids in addition to the folded DNA and nascent RNA chains. Incubation of the membrane-attached chromosomes with 1% Sarkosyl releases the folded chromosomes; this Sarkosyl treatment removes the membrane proteins and phospholipids, and halves the sedimentation velocity of the particles, but has no effect on the folded DNA and nascent RNA chains.Membrane-attached chromosomes cannot be isolated from amino acid-starved cells which have completed their rounds of DNA replication; all of the DNA then appears as released folded chromosomes. After resumption of protein synthesis, chromosome attachment to the membrane precedes the initiation of DNA replication. Controls strongly suggest that the changes observed, i.e. the attachment and release from the membrane of the folded chromosome, are related to the act of DNA replication itself.