Assembly of the translocase motor onto the preprotein-conducting channel

Spyridoula Karamanou, Vassiliki Bariami, Efrosyni Papanikou, Charalampos G. Kalodimos, Anastassios Economou

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


Bacterial protein secretion is catalysed by the SecYEG protein-conducting channel complexed with the SecA ATPase motor. To gain insight into the SecA-SecYEG interaction we used peptide arrays, thermodynamic quantification, mutagenesis and functional assays. Our data reveal that: (i) SecA binds with low affinity on several, peripheral, exposed SecYEG sites. This largely electrostatic association is modulated by temperature and nucleotides. (ii) Binding sites cluster in five major binding 'regions': three that are exclusively cytoplasmic and two that reach the periplasm. (iii) Both the N-terminal and c-terminal regions of SecA participate in binding interactions and share some sites. (iv) Several of these sites are essential for translocase catalysis. Our data provide residue-level dissection of the SecYEG-SecA interaction. Two models of assembly of SecA on dimeric SecYEG are discussed.

Original languageEnglish (US)
Pages (from-to)311-322
Number of pages12
JournalMolecular Microbiology
Issue number2
StatePublished - Oct 2008
Externally publishedYes


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