title: The Adhesion of Lactobacillus salivarius REN to a Human Intestinal Epithelial Cell Line Requires S-layer Proteins.
abstract: Lactobacillus salivarius REN, a novel probiotic isolated from Chinese centenarians, can adhere to intestinal epithelial cells and subsequently colonize the host. We show here that the surface-layer protein choline-binding protein A (CbpA) of L. salivarius REN was involved in adherence to the human colorectal adenocarcinoma cell line HT-29. Adhesion of a cbpA deletion mutant was significantly reduced compared with that of wild-type, suggesting that CbpA acts as an adhesin that mediates the interaction between the bacterium and its host. To identify the molecular mechanism of adhesion, we determined the crystal structure of a truncated form of CbpA that is likely involved in binding to its cell-surface receptor. The crystal structure identified CbpA as a peptidase of the M23 family whose members harbor a zinc-dependent catalytic site. Therefore, we propose that CbpA acts as a multifunctional surface protein that cleaves the host extracellular matrix and participates in adherence. Moreover, we identified enolase as the CbpA receptor on the surface of HT-29 cells. The present study reveals a new class of surface-layer proteins as well as the molecular mechanism that may contribute to the ability of L. salivarius REN to colonize the human gut.
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Ran
authors.initials: R
authors.lastname: Wang
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Lun
authors.initials: L
authors.lastname: Jiang
authors.affiliation: School of Food and Chemical Engineering, Beijing Technology and Business University, Beijing 100048, P. R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhang
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Hao
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Guo
authors.affiliation: Beijing Higher Institution Engineering Research Center of Animal Product, Beijing 100083, P. R. China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Sang
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing 100083, P. R. China.
authors.forename: Fazheng
authors.initials: F
authors.lastname: Ren
mesh_terms: D018829:Adhesins, Bacterial; D001422:Bacterial Adhesion; D004847:Epithelial Cells / Q000378:metabolism / Q000382:microbiology*; D019073:HT29 Cells; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000382:microbiology*; D000069996:Ligilactobacillus salivarius / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D018829:Adhesins, Bacterial; D008562:Membrane Glycoproteins; C055764:S-layer proteins