Exploring interactions of the S-layer protein of Lactobacillus acidophilus ATCC4356

FINA MARTIN, JOAQUINA; MARÍA MERCEDES PALOMINO; CUTINE AM; ALLIEVI MARIANA C; ZANINI SH; MARIÑO KV; BARQUERO A; RUZAL SANDRA M.

Paraná Entre Ríos

Congreso; LIV Reunion Anual de la Soc.Arg. de Inv. en Bioquímica y Biología Molecular; 2018

SAIB

Exploring interactions of the S-layer protein of Lactobacillus acidophilus ATCC4356Fina Martin J1,2, Palomino MM1,2, Cutine A3, Allievi MC1,2, Zanini SH1, Mariño KV3, Barquero A1,2, Ruzal SM1,2§1 Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica. Buenos Aires, Argentina. 2 CONICET- IQUIBICENE-mail: joaquinafinamartin@gmail.com3 Laboratorio de Glicómica Funcional y Molecular, Instituto de Biología y Medicina Experimental (IBYME), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) C1428, Buenos Aires, Argentina. Surface layer (S-layer) proteins constitute in some species of lactobacilli their outermost cell envelope and have been involved in modulating the host immune system and inhibit pathogenic virus and bacteria adhesion which has recently gained attention as a way to prevent infection. Here, we investigate interactions of purified surface layer (S-layer) proteins from Lactobacillus acidophilus ATCC 4356 cells and chimerical GFP?S-layer fusion proteins (containing different portions of the SlpA protein) with prokaryotic (peptidoglycan and lipoteichoic acids) and eukaryotic (mucin, fibronectin, collagen) macromolecules, as well as with viruses and bacterial, yeast and blood cells. The interaction targets of S-layers were analysed by means of Dot blot analysis and binding inhibition by agglutination, flow cytometry and solid phase assays. Our results show that the C-terminal portion of the S-layer protein presents lectin-type activity, interacting with different glycosylations, being the LTA (lipoteichoic acids) and mannose the preferred interactors. The interaction of the SlpA protein with viral particles was studied by means of a virulent activity test of herpes simplex virus type 1 (HSV-1), vesicular stomatitis virus (VSV), human adenovirus type 5 (AdV5) and bacteriophage J1. No virucidal activity was observed. However, interaction with viral particles enables to co-precipitate them with the protein after centrifugation, decreasing the viral titer but not bacteriophage´s, suggesting the interaction with glycosylated proteins of the virus. Alltogether these results may explain the pathogen exclusion effect reported for SlpA.