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：1984
卷号：81
期号：23
页码：7421-7425
DOI：10.1073/pnas.81.23.7421
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Precursors to two periplasmic proteins and one outer membrane protein were synthesized in a membrane-free extract from Escherichia coli programmed with plasmid DNA. In the presence of inverted plasma membrane vesicles from E. coli up to 25% of the precursor molecules were converted into their mature forms. Using externally added proteinase K as a probe, we found the processed proteins segregated within the membrane vesicles. By the same criteria, a small amount of each precursor also proved to be translocated, indicating that translocation and signal sequence cleavage are not necessarily coupled processes. Furthermore, we present conclusive evidence that the translocation step can occur post-translationally even as late as 60 min after the beginning of translation.
