Sarkar N, Paulus H
Proc Natl Acad Sci U S A. 1972 Dec;69(12):3570-4. doi: 10.1073/pnas.69.12.3570.
RNA polymerase has been purified from vegetative cells of Bacillus brevis and resolved into "core" enzyme and sigma factor. The purified enzyme is rapidly inactivated by incubation at low temperatures in the presence of 1-2 mM ATP, dATP, or NAD(+), while other nucleotides at this concentration have little or no effect. Inactivation is not accompanied by the incorporation of an adenylyl or phosphoryl moiety into RNA polymerase; nevertheless, it is essentially irreversible. DNA, high concentrations of glycerol, as well as low concentrations (1 mM) of orthophosphate protect RNA polymerase from the nucleotide-dependent inactivation.A similar inactivation of RNA polymerase in the presence of ATP is observed with crude preparations from Bacillus subtilis and Bacillus polymyxa. This phenomenon may represent a novel mode of regulation of transcription that does not involve a covalent modification of RNA polymerase or its interaction with other protein factors, but rather is due to a structural transition to an inactive form induced by small molecules.
已从短短芽孢杆菌的营养细胞中纯化出RNA聚合酶，并将其解析为“核心”酶和σ因子。纯化后的酶在1-2 mM ATP、dATP或NAD(+)存在的情况下，于低温孵育时会迅速失活，而在此浓度下的其他核苷酸几乎没有影响或完全没有影响。失活过程中不会有腺苷酰基或磷酰基部分掺入RNA聚合酶；然而，这基本上是不可逆的。DNA、高浓度甘油以及低浓度（1 mM）的正磷酸盐可保护RNA聚合酶免受核苷酸依赖性失活的影响。在枯草芽孢杆菌和多粘芽孢杆菌的粗提物中也观察到了在ATP存在下RNA聚合酶的类似失活现象。这种现象可能代表了一种新的转录调控模式，它不涉及RNA聚合酶的共价修饰或其与其他蛋白质因子的相互作用，而是由于小分子诱导的结构转变为无活性形式所致。
