Distribution and chemical characterization of regular arrays in the cell walls of strains of the genus Lactobacillus

The presence of regular arrays (RAs) in the cell walls of strains of the genus Lactobacillus was examined by electron microscopy. The RAs were found in 6 species including L. bulgaricus, L. helveticus, L. acidophilus, L. fermentum, L. brevis and L. buchneri. The RAs were composed of a protein with an apparent Mr ranging from about 41000 to 55000, depending on the species upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The amino acid composition of the RA proteins was shown to be acidic and hydrophobic. The antigenicity of the RA protein from L. buchneri appeared to be specific but not common among the RA proteins from the other lactobacilli.