Characterization of surface layer proteins and its role in probiotic properties of three Lactobacillus strains.
The objective of this study was the characterization of the surface layer proteins (SLPs) and their functional role in the probiotic activity of Lactobacillus helveticus fb213, L. acidophilus fb116 and L. acidophilus fb214. SLPs were extracted and identified by SDS-PAGE, circular dichroism spectra and LC-MS analysis. The results revealed that the molecular masses of the three proteins were 49.7 kDa, 46.0 kDa and 44.6 kDa, respectively. The secondary structures and amino acid compositions of the three proteins were found to be similar. After removing SLPs, the survival of the three lactobacilli in simulated gastric and intestinal juices was reduced by 2-3log as compared with survival of the intact cells. And the adhesion ability of the three strains to HT-29 cells decreased by 61%, 65% and 92%, respectively. SLPs also inhibited the adhesion and invasion of Escherichia coli ATCC 43893 to HT-29 cells. These results suggest that SLPs are advantageous barriers for lactobacilli in the gastrointestinal tract, and these proteins help make it possible for lactobacilli to serve their probiotic functions.
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
Jun
J
Meng
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
Xiao
X
Zhu
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
Shu-Ming
SM
Gao
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
Qiu-Xiang
QX
Zhang
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.
Zhen
Z
Sun
State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China. Electronic address: lurr2004@hotmail.com.
Rong-Rong
RR
Lu
D004345:Drug Industry; D019649:Food Industry; D019073:HT29 Cells; D006801:Humans; D007778:Lactobacillus / Q000378:metabolism* / Q000502:physiology; D007779:Lactobacillus acidophilus / Q000378:metabolism / Q000502:physiology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D019936:Probiotics / Q000378:metabolism*
D008562:Membrane Glycoproteins; C055764:S-layer proteins
Amino acid composition; Lactobacillus; Probiotic function; Secondary structure; Surface layer protein