Comparative genomic analysis of Lactobacillus rhamnosus GG reveals pili containing a human- mucus binding protein

• DOI: 10.1073/pnas.0908876106
• Publication Date: 2009-09-18T05:11:21Z
• Authors: Matti Kankainen; Lars Paulin; Soile Tynkkynen; Ingemar von Ossowski; Justus Reunanen; Pasi Partanen; Reetta Satokari; Satu Vesterlund; Antoni P. A. Hend...; Sarah Lebeer; Sigrid C. J. De K...; Jos Vanderleyden; Tuula Hämäläinen; Suvi Laukkanen; Noora Salovuori; Jarmo Ritari; Edward Alatalo; Riitta Korpela; Tiina Mattila-San...; Anna Lassig; Katja Hatakka; Katri T. Kinnunen; Heli Karjalainen; Maija Saxelin; Kati Laakso; Anu Surakka; Airi Palva; Tuomas Salusjärvi; Petri Auvinen; Willem M. de Vos
• Keywords: Pilin; Lactobacillus rhamnosus; Sortase

To unravel the biological function of widely used probiotic bacterium Lactobacillus rhamnosus GG, we compared its 3.0-Mbp genome sequence with similarly sized L. LC705, an adjunct starter culture exhibiting reduced binding to mucus. Both genomes demonstrated high identity and synteny. However, for both strains, genomic islands, 5 in GG 4 punctuated colinearity. A significant number strain-specific genes were predicted these islands (80 72 LC705). The GG-specific included coding bacteriophage components, sugar metabolism transport, exopolysaccharide biosynthesis. One island only found contained 3 secreted LPXTG-like pilins (spaCBA) a pilin-dedicated sortase. Using anti-SpaC antibodies, physical presence cell wall-bound pili was confirmed by immunoblotting. Immunogold electron microscopy showed that SpaC pilin is located at pilus tip but also sporadically throughout structure. Moreover, adherence strain human intestinal mucus blocked antiserum abolished mutant carrying inactivated spaC gene. Similarly, purified protein. We conclude essential interaction likely explains ability persist tract longer than LC705 during intervention trial. mucus-binding on surface nonpathogenic Gram-positive bacterial reveals previously undescribed mechanism selected lactobacilli host tissues.