PMID:10413486
| Citation |
Kaufmann, A, Manting, EH, Veenendaal, AK, Driessen, AJ and van der Does, C (1999) Cysteine-directed cross-linking demonstrates that helix 3 of SecE is close to helix 2 of SecY and helix 3 of a neighboring SecE. Biochemistry 38:9115-25 |
|---|---|
| Abstract |
Preprotein translocation in Escherichia coli is mediated by translocase, a multimeric membrane protein complex with SecA as the peripheral ATPase and SecYEG as the translocation pore. Unique cysteines were introduced into transmembrane segment (TMS) 2 of SecY and TMS 3 of SecE to probe possible sites of interaction between the integral membrane subunits. The SecY and SecE single-Cys mutants were cloned individually and in pairs into a secYEG expression vector and functionally overexpressed. Oxidation of the single-Cys pairs revealed periodic contacts between SecY and SecE that are confined to a specific alpha-helical face of TMS 2 and 3, respectively. A Cys at the opposite alpha-helical face of TMS 3 of SecE was found to interact with a neighboring SecE molecule. Formation of this SecE dimer did not affect the high-affinity binding of SecA to SecYEG and ATP hydrolysis, but blocked preprotein translocation and thus uncouples the SecA ATPase activity from translocation. Conditions that prevent membrane deinsertion of SecA markedly stimulated the interhelical contact between the SecE molecules. The latter demonstrates a SecA-mediated modulation of the protein translocation channel that is sensed by SecE. |
| Links |
PubMed Online version:10.1021/bi990539d |
| Keywords |
Adenosine Triphosphatases/metabolism; Amino Acid Sequence; Bacterial Proteins/antagonists & inhibitors; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Biological Transport/genetics; Cell Membrane/chemistry; Cross-Linking Reagents/chemistry; Cysteine/chemistry; Cysteine/genetics; Dimerization; Escherichia coli Proteins; Leucine/genetics; Membrane Proteins/antagonists & inhibitors; Membrane Proteins/chemistry; Membrane Proteins/genetics; Membrane Transport Proteins; Molecular Sequence Data; Mutagenesis, Site-Directed; Oxidation-Reduction; Peptide Fragments/antagonists & inhibitors; Peptide Fragments/chemistry; Peptide Fragments/genetics; Plasmids/chemical synthesis; Protein Structure, Secondary |
| edit table |
Significance
You can help EcoliWiki by summarizing why this paper is useful
Useful Materials and Methods
You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.
Annotations
<annotationlinks/>
EcoliWiki Links
Add links to pages that link here (e.g. gene, product, method pages)
References
See Help:References for how to manage references in EcoliWiki.