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：1988
卷号：85
期号：21
页码：7882-7886
DOI：10.1073/pnas.85.21.7882
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The activity of the cII protein of phage lambda is probably the critical controlling factor in the choice of the lytic or lysogenic pathway by an infecting virus. Previous work has established that cII activity is regulated through the turnover of cII protein; the products of the hflA and hflB loci of Escherichia coli are needed for a degradative reaction, and lambda cIII functions in stabilizing cII. By using the cloned hflA locus, we have purified a cII-cleaving enzyme that we term HflA. Purified HflA contains three polypeptides; at least two of the subunits are products of the hflA region, and the third is probably a cleavage product of the larger of these two hflA-encoded polypeptides. The HflA protease activity cleaves cII to small fragments. We conclude that the switch between lambda developmental pathways involves regulated cleavage of cII by the specific protease HflA.
