Comparative Genomics of Transporter Proteins in Lactic Acid Bacteria

Although lactic acid bacteria (LABs) possess unique metabolic and physiological characteristics that have crucial effects on the transport of substances both into and out of the cell, there is still a lack of systematic research on membrane transporters in LABs and their roles in material transport. In this study, genomic data for the species Lactobacillus delbrueckii, Streptococcus thermophilus, Leuconostoc lactis, Pediococcus lactis, Lactococcus garvieae, and Bifidobacterium lactis were analyzed to identify the associated transport systems, including what kind of substances are transported. As part of a comparative genomics approach, we used the G-BLAST and AveHAS programs in the TCDB database to screen for transport proteins and clarify the distribution of these proteins in different Lactobacillus strains, allowing for further prediction of their transport substrates. Studies have shown that the distributions of these transporters differ among the selected LAB strains. Through screening and tabulation, we found that the content of transporters in the six LAB proteomes was greater than 20%, with the dominance of the large transporter group indicating complex metabolic and probiotic effects. Furthermore, it was found that the LAB strains contain a variety of homologs of drug-efflux proteins, which may make them resistant to antibiotics, as well as a large number of toxin-related transporters. This study allowed for reasonable predictions of the roles of toxin-related proteins in LABs, and further research on these proteins may be valuable for understanding the probiotic effects of LABs that arise through competition. The study of LAB transporters and the prediction of their functions might support a better understanding of the metabolic and physiological activities of these bacteria. In the future, we aim to extract DNA from laboratory strains and perform PCR amplification using suitable primers designed by us. Through comparison of the obtained gene sequences with those reported in this study, we can explore the differences among them.