Molecular analysis of adhesion protein produced by lactic acid bacteria including Bifidobacterium for probiotic application

本研究的目的是阐明双歧杆菌和乳杆菌与糖缀合物的糖链作为肠细胞的粘附因子的结合机制。在测试菌株中，两歧双歧杆菌、罗伊氏乳杆菌和嗜酸乳杆菌菌株与糖缀合物的糖链结合。有趣的是，这些细菌抑制了病原体如幽门螺杆菌与受体分子的结合，这表明这些乳酸菌有助于在病原体定植的早期阶段预防感染。通过印迹法在3株菌株中发现分子量为50-60 Kda的糖结合蛋白。然后克隆3个蛋白的基因并确定其序列。3个蛋白的同源性不高。此外，从嗜酸乳杆菌中发现分子量为50Kda的推定糖结合蛋白的重组蛋白可以与含有甘露糖的糖链结合，而从双歧杆菌和罗伊氏乳杆菌中发现的推定糖结合蛋白的重组蛋白没有与糖链结合。进一步的实验需要检验两歧双歧杆菌和罗伊氏乳杆菌推测的糖结合蛋白的结合能力。本研究表明嗜酸乳杆菌产生的50 kda蛋白为凝集素型乳脂素。

Objective of this research is to elucidate binding mechanisms of bifidobacteria and lactobacilii to sugar chains of the glycoconjugates as an adhesion factor to intestinal cells. Of tested strains, Bifidobacterium bifidum, Lactobacillus reuteri and Lactobacillus acidophilus strains were shown to binding to the sugar chains of glycoconjugates. Interestingly, these bacteria inhibited the binding of pathogens such as Helicobacter pylori to the receptor molecules, suggesting that these lactic acid bacteria help to prevent infection in an early stage of colonization in pathogens.The putative sugar-binding proteins with molecular weights of 50-60 Kda were found in three strains by blotting procedures. Then, the genes of three proteins were cloned and the sequences were determined. The homology among three proteins was not high. Further, the recombinant proteins of putative sugar-binding proteins with MW of 50Kda from L.acidophilus was found to bind the sugar chains containing mannose, while another two recombinant proteins of putative sugar-binding proteins from B.bifidum and L.reuteri did not show any binding to sugar chains. Further experiments need to examine that the binding ability of putative sugar-binding proteins from B.bifidum and L.reuteri. The present study showed that 50-kDa protein produced by L. acidophilus is lectin type dadhesin.