Composition and activity of the non-canonical Gram-positive SecY2 complex

Mikaila Jayaweera Bandara, Robin Corey, Remy Martin, Ariel Blocker, Howard Jenkinson, Ian Collinson

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)
1244 Downloads (Pure)


The accessory Sec system in Streptococcus gordonii DL1 is a specialized export system that transports a large serine-rich repeat protein, Hsa, to the bacterial surface. The system is comprised of core proteins SecA2, SecY2, and accessory Sec proteins Asp1-Asp5. Similar to canonical SecYEG, SecY2 forms a channel for translocation of the Hsa adhesin across the cytoplasmic membrane. Accessory Sec proteins Asp4 and Asp5 have been suggested to work alongside SecY2 to form the translocon; akin to the associated SecY, SecE and SecG of the canonical system (SecYEG). To test this theory, S. gordonii secY2, asp4, and asp5 were co-expressed in Escherichia coli. The resultant complex was subsequently purified and its composition was confirmed by mass spectrometry to be: SecY2-Asp4-Asp5. Like SecYEG, the non-canonical complex activates the ATPase activity of the SecA motor (SecA2). This study also shows that Asp4 and Asp5 are necessary for optimal adhesion of S. gordonii to glycoproteins gp340 and fibronectin, known Hsa binding partners, as well as for early stage biofilm formation. This work opens new avenues for understanding the structure and function of the accessory Sec system.
Original languageEnglish
Pages (from-to)21474-21484
Number of pages11
JournalJournal of Biological Chemistry
Issue number41
Publication statusPublished - 7 Oct 2016


  • ATPase
  • complex
  • membrane
  • secretion
  • transport
  • SecY2
  • Streptococcus gordonii
  • accessory Sec system
  • translocon


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