Purification and Characterization of RNA polymerase from halophilic archaebacteria.

嗜盐菌是一种嗜盐古细菌，生长在极端的嗜盐环境中。细胞内K^+的浓度也非常高。盐藻基因转录的机制和参与这一过程的RNA聚合酶的性质仍有待研究。我们试图纯化RNA聚合酶，它需要高盐浓度才能发挥作用。Zilling等人（1978）从一种相关的cutirubrum细胞中鉴定出了一种高分子量的RNA聚合酶。在盐藻细胞的粗提取物中，我们检测到两种RNA聚合酶的活性，一种需要高浓度的盐才能达到最大活性，另一种则不需要。高要求的RNA聚合酶通过PEI处理、Buty-Toyopearl和甘油梯度离心纯化到约1000倍。部分纯化的RNA聚合酶需要3M NaCl才能达到最大活性，dna依赖性RNA合成在40℃下持续至少90分钟。该酶对利福平和α -amanitin均有抗性，但对木质素敏感，木质素是流感病毒RNA聚合酶的有效抑制剂。通过甘油梯度离心，估计其分子量约为45 kDs。酶的进一步纯化和酶结构的详细分析正在进行中。

Halobacterium halobium, one of the halophilic archaebacteria, grows in extreme halophilic environments. The intracellular concentration of K^+ is also extremely high. The mechanisum of gene transcription in H.halobium and the nature of RNA polymerase involved in this process are still remained to study. We tried to purify the RNA polymerase which requires high salt concentrations for function.Zilling et al. (1978) identified a high-molecular-weight RNA polymerase from a related H.cutirubrum.In crude extract of H.halobium cells, we detected two RNA polymerase activities, one requiring high concentrations of salt for maximun activity and the other not requiring it. The high-requiring RNA polymerase was purified up to about 1,000-fold by PEI iteatment, Buty-Toyopearl and glycerol gradient centrifugation. The partially purified RNA polymerase required 3M NaCl for maximum activity DNA-dependent RNA synthesis continued at least until 90 min at 40ﾟC.The enzyme was resistant to both rifampicin and alpha-amanitin, but was sensitive to lignin, which is a potent inhibitor of influenza virus RNA polymerase. The molecular weight was estimated to be about 45 kDs by glycerol gradient centrifugation. Futher purification of the enzyme and detailed analysis of the enzyme structure are in progress.