Cloning and expression of the C-terminal Motif of the S-layer from Lactobacillus acidophilus ATCC 4356

MARIANO PRADO ACOSTA; MARÍA MERCEDES PALOMINO; MARIANA C ALLIEVI; CARMEN SÁNCHEZ RIVAS; SANDRA M RUZAL

Villa Carlos Paz

Congreso; XLIV Reunión Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2008

Sociedad Argentina de Investigación Bioquímica y Biología Molecular.

Cloning and expression of the C-terminal Motif of the S-layer from Lactobacillus acidophilus ATCC 4356 Mariano Prado-Acosta, M. Mercedes Palomino, Mariana C. Allievi, Carmen Sanchez Rivas and Sandra M. Ruzal Universidad de Buenos Aires. FCEyN. Dpto. de Química Biológica. Bs As. Argentina XLIV Reunión Anual de SAIB, Villa Carlos Paz, Córdoba del 8 al 11 de Noviembre 2008 Lactobacillus acidophilus is one of the major species of the genus Lactobacillus found in human and animal intestines and believed to possess probiotic properties. In the outermost envelope of Lb. acidophilus ATCC 4356, an S-layer structure is found. It is composed of 45Kb protein monomers encoded by a slpA gene. The lytic activity of this S-layer was showed against Salmonella newport as a pathogen model. The activity was not detected against Bacillus and Lactobacillus cell walls. This gene was sequenced and showed 99% homology with other slpA from Lb. acidophilus strains and in silico analysis of the deduced protein showed a C-terminal motif which aligned with murein hydrolases of several Lactobacillus strains. The C-terminal motif was cloned in plasmid pHMC05 with an IPTG inducible pSpac promoter. The plasmid introduced in E. coli JM109 showed high instability and decreased growths in particular when IPTG was present.We assume that expression resulted in a lethal effect. Therefore we introduced it in Bacillus subtilis 168 and induced expression by adding IPTG. Activity of the C-terminal S-layer was evident in Bacillus subtilis, where it conserved the murein hydrolase activity.  The new activity here described may contribute to the already reported probiotic properties of this bacterium.