期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1973
卷号：70
期号：6
页码：1865-1869
DOI：10.1073/pnas.70.6.1865
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The activity of the sigma subunit of the RNA polymerase of Bacillus subtilis decreases markedly during the first 2 hr of sporulation. Moreover, sigma activity remains deficient throughout the sporulation process and in dormant spores. The time course of changes in RNA polymerase during sporulation indicates that alterations in the core of RNA polymerase occur after the loss of sigma activity. Core RNA polymerase purified after the second and before the ninth hour of sporulation fails to respond to vegetative sigma subunit in vitro and contains variable amounts of a 110,000-dalton polypeptide in place of the {beta}' subunit. Core RNA polymerase purified from dormant spores has a subunit structure indistinguishable from vegetative core enzyme. RNA polymerase purified by antibody precipitation from an extract of a mixture of sporulating and excess vegetative cells separately labeled with two different radioisotopes contains {beta}' subunit and no 110,000-dalton polypeptide. However, RNA polymerase purified from sporulating bacteria in the absence of excess vegetative cells progressively loses the {beta}' subunit at each stage of purification even in the presence of the protease inhibitor, phenylmethyl sulfonyl fluoride. These findings suggest that the alteration of the {beta}' subunit is due to proteolysis in vitro.
