Molecular characterization of fibronectin-binding protein of Lactobacillus pentosus and Lactobacillus plantarum strains

Abstract

The ability of lactobacilli to adhere to vaginal epithelial surfaces and intestinal tracts is believed to be important to allow colonization and host interaction for persistence. Bacterial adhesins molecules are proteins of which the human host fibronectin serves as a substrate for the attachment of bacteria and play a significant role in cellular processes. Lactobacilli, especially L. pentosus and L. plantarum strains are closely related in their fermentative characteristics and are versatile in colonizing both the human, dairy and plant micro-ecology. Bioinformatic tools were used to characterize the secondary and putative three-dimensional structures of fibronectin-binding proteins (FnBP) predicted in the genome of L. pentosus and L. plantarum strains. The FnBP gene tree and in silico PCR clearly shows that L. pentosus KCA1 fibronectin-binding protein can be distinguished from other pentosus and plantarum strains, thus suggesting a potential marker for differentiation. In addition, FnBP of L. pentosus KCA1 contains 56 leucine, and 36 valine residues, which is higher when compared with other selected strains. Also the number of carbon C (2862) and hydrogen H atoms (4551) are slightly higher than other strains, thus suggesting the uniqueness of the KCA1 FnBP. The 3-D model generated a QMEAN Z-score of -2.33, -2.74, -2.67, and -2.77 for L. pentosus KCA1, L. pentosus IG1, L. pentosus MP-10 and L. plantarum WCFS1 respectively. In vitro fibronectin-binding capability of L. pentosus KCA1 using a fibronectin-binding assay showed that L. pentosus KCA1 can effectively bind to anti-human fibronectin antibody.