SECY IS AN INDISPENSABLE COMPONENT OF THE PROTEIN SECRETORY MACHINERY OF ESCHERICHIA-COLI

被引:47
作者
NISHIYAMA, K
KABUYAMA, Y
AKIMARU, J
MATSUYAMA, S
TOKUDA, H
MIZUSHIMA, S
机构
[1] Institute of Applied Microbiology, University of Tokyo, Yayoi, Bunkyo-ku
关键词
SECY; PROTEIN SECRETION; RECONSTITUTION; OMPT; ANTI-SECY ANTIBODY;
D O I
10.1016/0005-2736(91)90015-Z
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Using a reconstitution system for protein translocation, the involvement of SecY in the translocation of secretory proteins across the cytoplasmic membrane of Escherichia coli was studied. Anti-SecY antibodies raised against the N-and C-terminal sequences prevented the functional reconstitution of the translocation system. Depletion of SecY from the solubilized membrane preparation was performed by treatment with anti-SecY IgG, followed by removal of IgG with protein A-agarose. The SecY-depleted preparation was inactive as to functional reconstitution. However, reconstitution with it was demonstrated in the presence of a protein fraction, which was released from the anti-SecY immunoprecipitate upon addition of the SecY fragment used to raise the antibody. Reconstitution with the SecY-depleted membrane fraction was also demonstrated in the presence of a purified SecY preparation. OmpT proteinase specifically cleaved SecY in the solubilized membrane preparation. The cleavage was accompanied by a decrease in the reconstituted activity. Based on these findings we conclude that SecY is an indispensable component of the secretory machinery.
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页码:89 / 97
页数:9
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