%0 Journal Article %A Candela, Marco %A Biagi, Elena %A Centanni, Manuela %A Turroni, Silvia %A Vici, Manuela %A Musiani, Francesco %A Vitali, Beatrice %A Bergmann, Simone %A Hammerschmidt, Sven %A Brigidi, Patrizia %T Bifidobacterial enolase, a cell surface receptor for human plasminogen involved in the interaction with the host %D 2009 %J Microbiology, %V 155 %N 10 %P 3294-3303 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.028795-0 %K PEP, phosphoenolpyruvate %K Plg, plasminogen %K 2-PGE, 2-phosphoglycerate %K EACA, ϵ-aminocaproic acid %I Microbiology Society, %X The interaction with the host plasminogen/plasmin system represents a novel component in the molecular cross-talk between bifidobacteria and human host. Here, we demonstrated that the plasminogen-binding bifidobacterial species B. longum, B. bifidum, B. breve and B. lactis share the key glycolytic enzyme enolase as a surface receptor for human plasminogen. Enolase was visualized on the cell surface of the model strain B. lactis BI07. The His-tagged recombinant protein showed a high affinity for human plasminogen, with an equilibrium dissociation constant in the nanomolar range. By site-directed mutagenesis we demonstrated that the interaction between the B. lactis BI07 enolase and human plasminogen involves an internal plasminogen-binding site homologous to that of pneumococcal enolase. According to our data, the positively charged residues Lys-251 and Lys-255, as well as the negatively charged Glu-252, of the B. lactis BI07 enolase are crucial for plasminogen binding. Acting as a human plasminogen receptor, the bifidobacterial surface enolase is suggested to play an important role in the interaction process with the host. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.028795-0