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

Bandara, M. , Corey, R. A., Martin, R., Skehel, J. M., Blocker, A. J., Jenkinson, H. F. and Collinson, I. (2016) Composition and activity of the non-canonical gram-positive SecY2 complex. Journal of Biological Chemistry, 291(41), pp. 21474-21484. (doi: 10.1074/jbc.m116.729806) (PMID:27551046) (PMCID:PMC5076819)

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.

• Item Type: Articles
• Additional Information: This work supported by Biotechnology and Biological Sciences Research Council Project Grant BB/I008675/1 (to I. C.), Medical Research Council Doctoral Training Grant 2011-G1001606 (to M. B.), Biotechnology and Biological Sciences Research Council South West Bioscience Doctoral Training Partnership (to R. A. C.), and University of Bristol postgraduate scholarship (to R. M.).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Jayaweera Bandara, Dr Mikaila
• Authors: Bandara, M., Corey, R. A., Martin, R., Skehel, J. M., Blocker, A. J., Jenkinson, H. F., and Collinson, I.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: Journal of Biological Chemistry
• Publisher: American Society for Biochemistry and Molecular Biology
• ISSN: 0021-9258
• ISSN (Online): 1083-351X
• Published Online: 22 August 2016
• Copyright Holders: Copyright © 2016 The American Society for Biochemistry and Molecular Biology, Inc.
• First Published: First published in Journal of Biological Chemistry 291(41): 21474-21484
• Publisher Policy: Reproduced under a Creative Commons License