本项目主要研究目标为表征乳杆菌S-层蛋白（SLP）功能结构域，探明S-层蛋白自组装机制和肠道黏附机制；并研究S-层蛋白修饰脂质体介导乳源功能肽肠道转运、外排和内化机理。本项目拟分离纯化嗜酸乳杆菌、瑞士乳杆菌、卷曲乳杆菌、短乳杆菌、约氏乳杆菌等乳杆菌的S-层蛋白，筛选具有体外自组装性能、肠道黏附性能、耐胃肠道蛋白酶水解性能的乳杆菌S-层蛋白；克隆乳杆菌S-层蛋白基因序列，表征S-层蛋白自组装结构域、肠道黏附结构域及细胞壁锚定结构域，同时探明S-层蛋白肠道黏附相关受体；利用Caco-2细胞为肠道吸收模型，研究S-层蛋白修饰脂质体介导乳源功能肽的肠道吸收机理，探明S-层蛋白修饰乳肽脂质体肠道转运机制、外排机制和内化机制；评价S-层蛋白修饰乳肽脂质体的生物安全性，以保证其在食品工业中的安全应用。本项目为乳杆菌S-层蛋白、乳源功能肽在功能性食品市场的应用提供了理论研究依据。

The main aim of this project is to identify and characterize functional domain of S-layer protein (SLP) of Lactobacillus and ascertain the self-assembly and intestinal adhesion mechanism of SLP. The intestinal transport, efflux and internalization mechanism of milk-derived bioactive peptide embedded with SLP coated-liposome is also researched. The SLPs of Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus crispatus, Lactobacillus brevis and Lactobacillus johnsonii will be purified and characterized. The properties including self-assembly ability, intestinal adhesion ability, resistance to gastric intestinal protease ability of SLPs are going to be compared to choose the proper SLP as the research object. The Lactobacillus SLP gene sequence will be cloned to characterize the self-assembly domain, intestinal adhesion domain and cell wall anchoring domain. The intestinal receptor of SLP is also clarified. Caco-2 cell is used as intestinal absorption model to research intestinal absorption mechanism of milk-derived bioactive peptide embedded with SLP-coated-liposome. The intestinal transport, efflux and internalization mechanism is going to be clarified. The biological safety of peptide embedded with SLP-coated-liposome is evaluated to ensure the safety of its application in food industry. This project provides basic theory research for SLP of Lactobacillus and milk-derived bioactive peptide used in functional food market.