These two authors contributed equally to this study.
Unique secreted–surface protein complex of Lactobacillus rhamnosus, identified by phage display
Article first published online: 11 DEC 2012
© 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 1, pages 1–17, February 2013
How to Cite
MicrobiologyOpen 2013; 2(1): 1–17
- Issue published online: 13 FEB 2013
- Article first published online: 11 DEC 2012
- Manuscript Accepted: 25 OCT 2012
- Manuscript Received: 17 OCT 2012
- Massey University
- Palmerston North Medical Research Foundation
- New Zealand Foundation for Research and Technology. Grant Number: C03X0701
- Fonterra Co-operative Group Ltd.
- Ministry of Science and Innovation
- cell surface;
Proteins are the most diverse structures on bacterial surfaces; hence, they are candidates for species- and strain-specific interactions of bacteria with the host, environment, and other microorganisms. Genomics has decoded thousands of bacterial surface and secreted proteins, yet the function of most cannot be predicted because of the enormous variability and a lack of experimental data that would allow deduction of function through homology. Here, we used phage display to identify a pair of interacting extracellular proteins in the probiotic bacterium Lactobacillus rhamnosus HN001. A secreted protein, SpcA, containing two bacterial immunoglobulin-like domains type 3 (Big-3) and a domain distantly related to plant pathogen response domain 1 (PR-1-like) was identified by screening of an L. rhamnosus HN001 library using HN001 cells as bait. The SpcA-“docking” protein, SpcB, was in turn detected by another phage display library screening, using purified SpcA as bait. SpcB is a 3275-residue cell-surface protein that contains general features of large glycosylated Serine-rich adhesins/fibrils from gram-positive bacteria, including the hallmark signal sequence motif KxYKxGKxW. Both proteins are encoded by genes within a L. rhamnosus-unique gene cluster that distinguishes this species from other lactobacilli. To our knowledge, this is the first example of a secreted-docking protein pair identified in lactobacilli.