Studying the Stability of S-Layer Protein of Lactobacillus Acidophilus ATCC 4356 in Simulated Gastrointestinal Fluids Using SDS-PAGE and Circular Dichroism

Crystalline arrays of proteinaceous subunits forming surface layers (s-layers) are now recognized as one of the most common outermost cell envelope components of prokaryotic organisms. the surface layer protein of lactobacillus acidophilus atcc4356 is composed of a single species of protein of apparent molecular weight of 43-46 kda. considering the lactobacillus acidophilus atcc4356 having the s-layer is stable in harsh gastrointestinal (gi) conditions, a protective role against destructive gi factors which has been proposed for these nanostructures. it opens interesting perspectives in the using and development of this s-layer as a protective coat for oral administration of unstable drug nanocarriers. to achieve this goal, it is necessary to study the in-vitro stability of the s-layers in the simulated gastrointestinal fluids (sgif). this study was planned to evaluate the in-vitro stability of the extracted s-layer protein of lactobacillus acidophilus atcc4356 in sgif using it as a protective coat in oral drug delivery. sodium dodecyl sulfate gel electrophoresis (sds-page) and circular dichroism (cd) spectroscopy were used to study the stability of the s-layer protein incubated in sgif. both the sds-page and cd spectra results showed that lactobacillus acidophilus atcc4356 s-layer protein is stable in simulated gastric fluid (sgf) with ph = 2 up to 5 min. it is stable in sgf ph = 3.2 and above it, with and without pepsin. it is also stable in all the simulated intestinal fluids. this s-layer is also stable in all of the simulated intestinal fluids.