title: Composition and Activity of the Non-canonical Gram-positive SecY2 Complex.
abstract: 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 composed of core proteins SecA2 and 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, similar 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.
authors.affiliation: From the School of Oral and Dental Sciences, Lower Maudlin Street, Bristol BS1 2LY.|the School of Biochemistry and.|School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, and.
authors.forename: Mikaila
authors.initials: M
authors.lastname: Bandara
authors.affiliation: the School of Biochemistry and.
authors.forename: Robin A
authors.initials: RA
authors.lastname: Corey
authors.affiliation: the School of Biochemistry and.
authors.forename: Remy
authors.initials: R
authors.lastname: Martin
authors.affiliation: Biological Mass Spectrometry and Proteomics, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom.
authors.forename: J Mark
authors.initials: JM
authors.lastname: Skehel
authors.affiliation: the School of Biochemistry and.|School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, and.
authors.forename: Ariel J
authors.initials: AJ
authors.lastname: Blocker
authors.affiliation: From the School of Oral and Dental Sciences, Lower Maudlin Street, Bristol BS1 2LY.
authors.forename: Howard F
authors.initials: HF
authors.lastname: Jenkinson
authors.affiliation: the School of Biochemistry and ian.collinson@bristol.ac.uk.
authors.forename: Ian
authors.initials: I
authors.lastname: Collinson
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D006801:Humans; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000069816:SEC Translocation Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D054773:Streptococcus gordonii / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins
chemical_list: D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; C108174:DMBT1 protein, human; D004268:DNA-Binding Proteins; D011956:Receptors, Cell Surface; D000069816:SEC Translocation Channels; D025521:Tumor Suppressor Proteins
keywords: ATPase; SecY2; Streptococcus gordonii; accessory Sec system; complex; membrane; secretion; translocon; transport