Surface displaced alfa-enolase of Lactobacillus plantarum is a fibronectin binding protein
Surface displaced alfa-enolase of Lactobacillus plantarum is a fibronectin binding protein
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DOI：
10.1186/1475-2859-8-14
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发表时间：
2009-02-16
影响因子：
6.4
通讯作者：
Sacco, Margherita
中科院分区：
文献类型：
--
作者：
Castaldo, Cristiana;Vastano, Valeria;Sacco, Margherita
背景：乳酸菌属乳酸菌和双歧杆菌属乳酸菌是人类肠道微生物群中最重要的健康促进菌群之一。它们在肠道内的保护作用包括与入侵病原体竞争生态位和代谢基质。在提供健康益处的必要特征中，共生微生物必须具有粘附人类肠道细胞的能力，从而在肠道中定植。对乳酸菌与人肠细胞粘附机制的研究表明，参与这种相互作用的因素在不同种类和菌株之间差异较大，主要是细菌粘附素与细胞外基质或黏液蛋白的相互作用。我们研究了植物乳杆菌（Lactobacillus plantarum）的粘附特性，这是健康个体的一种人类微生物群。结果：我们鉴定了植物乳杆菌LM3细胞表面蛋白（48 kDa），该蛋白特异性结合人纤维连接蛋白（Fn），这是一种细胞外基质蛋白。质谱分析证实该蛋白为植物乳杆菌ena1基因的产物，编码ena1 α烯醇化酶。免疫电镜证实了EnoA1的表面定位。在携带ena1零突变的突变株LM3-CC1中，无论是用抗烯醇化酶Western blot还是用fn覆盖免疫印迹法都无法检测到48 kDa的粘附素。此外，通过粘附实验，我们发现LM3- cc1细胞与纤维连接蛋白包被表面的结合效率低于野生型细胞，从而证明了表面移位的ena1蛋白对L. plantarum LM3与纤维连接蛋白粘附的重要性。结论：在病原体或共生菌定植过程中，与宿主组织的粘附是至关重要的早期步骤。通过研究LM3和LM3- cc1表面蛋白，我们证实了植物乳杆菌Eno A1 α烯醇化酶参与了fn结合。由于植物乳杆菌基因组中存在enoA2基因的表达，分离出l3 - cc1菌株成为可能，这使得我们有可能首次定量比较野生型和突变型菌株的粘附性，并无疑地评估植物乳杆菌Eno A1作为纤维连接蛋白结合蛋白的作用。
Background: Lactic acid bacteria of the genus Lactobacillus and Bifidobacterium are one of the most important health promoting groups of the human intestinal microbiota. Their protective role within the gut consists in out competing invading pathogens for ecological niches and metabolic substrates. Among the features necessary to provide health benefits, commensal microorganisms must have the ability to adhere to human intestinal cells and consequently to colonize the gut. Studies on mechanisms mediating adhesion of lactobacilli to human intestinal cells showed that factors involved in the interaction vary mostly among different species and strains, mainly regarding interaction between bacterial adhesins and extracellular matrix or mucus proteins. We have investigated the adhesive properties of Lactobacillus plantarum, a member of the human microbiota of healthy individuals.Results: We show the identification of a Lactobacillus plantarum LM3 cell surface protein (48 kDa), which specifically binds to human fibronectin (Fn), an extracellular matrix protein. By means of mass spectrometric analysis this protein was identified as the product of the L. plantarum enoA1 gene, coding the EnoA1 alfa-enolase. Surface localization of EnoA1 was proved by immune electron microscopy. In the mutant strain LM3-CC1, carrying the enoA1 null mutation, the 48 kDa adhesin was not anymore detectable neither by anti-enolase Western blot nor by Fn-overlay immunoblotting assay. Moreover, by an adhesion assay we show that LM3-CC1 cells bind to fibronectin-coated surfaces less efficiently than wild type cells, thus demonstrating the significance of the surface displaced EnoA1 protein for the L. plantarum LM3 adhesion to fibronectin.Conclusion: Adhesion to host tissues represents a crucial early step in the colonization process of either pathogens or commensal bacteria. We demonstrated the involvement of the L. plantarum Eno A1 alfa-enolase in Fn-binding, by studying LM3 and LM3-CC1 surface proteins. Isolation of LM3-CC1 strain was possible for the presence of expressed enoA2 gene in the L. plantarum genome, giving the possibility, for the first time to our knowledge, to quantitatively compare adhesion of wild type and mutant strain, and to assess doubtless the role of L. plantarum Eno A1 as a fibronectin binding protein.