The SecA Subunit of Escherichia coli Preprotein Translocase Is Exposed to the Periplasm
نویسندگان
چکیده
منابع مشابه
The SecA subunit of Escherichia coli preprotein translocase is exposed to the periplasm.
SecA undergoes conformational changes during translocation, inserting domains into and across the membrane or enhancing the protease resistance of these domains. We now show that some SecA bound at SecYEG is accessible from the periplasm to a membrane-impermeant probe in cells with a permeabilized outer membrane but an intact plasma membrane.
متن کاملSecA is an intrinsic subunit of the Escherichia coli preprotein translocase and exposes its carboxyl terminus to the periplasm.
SecA is the dissociable ATPase subunit of the Escherichia coli preprotein translocase, and cycles in a nucleotide-modulated manner between the cytosol and the membrane. Overproduction of the integral subunits of the translocase, the SecY, SecE and SecG polypeptides, results in an increased level of membrane-bound SecA. This fraction of SecA is firmly associated with the membrane as it is resist...
متن کاملStructure of dimeric SecA, the Escherichia coli preprotein translocase motor.
SecA is the preprotein translocase ATPase subunit and a superfamily 2 (SF2) RNA helicase. Here we present the 2 A crystal structures of the Escherichia coli SecA homodimer in the apo form and in complex with ATP, ADP and adenosine 5'-[beta,gamma-imido]triphosphate (AMP-PNP). Each monomer contains the SF2 ATPase core (DEAD motor) built of two domains (nucleotide binding domain, NBD and intramole...
متن کاملSubunit dynamics in Escherichia coli preprotein translocase.
SecY, SecE, and band 1 copurify as the SecY/E integral membrane domain of Escherichia coli preprotein translocase. To measure the in vivo association of these polypeptides and assay possible exchange, plasmid-borne secY and secE genes were placed under control of the ara regulon and fused to DNA encoding the influenza hemagglutinin epitope. Cells were incubated with [35S]methionine, grown for a...
متن کاملIn vivo cross-linking of the SecA and SecY subunits of the Escherichia coli preprotein translocase.
Precursor protein translocation across the Escherichia coli inner membrane is mediated by the translocase, which is composed of a heterotrimeric integral membrane protein complex with SecY, SecE, and SecG as subunits and peripherally bound SecA. Cross-linking experiments were conducted to study which proteins are associated with SecA in vivo. Formaldehyde treatment of intact cells results in th...
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ژورنال
عنوان ژورنال: Journal of Bacteriology
سال: 1998
ISSN: 0021-9193,1098-5530
DOI: 10.1128/jb.180.21.5776-5779.1998