Fig. 7
From: LsrB-based and temperature-dependent identification of bacterial AI-2 receptor
Schematic chart of strategy for binding of LsrB to endogenous AI-2 or exogenous AI-2. The extent of LsrB binding to endogenous AI-2 was evaluated using an AI-2 assay, which showed that recombinant LsrB (BL21) bound to endogenous AI-2 (produced by wild-type strain BL21) and was released from LsrB (BL21) at 50 or 60 °C. However, since the luxS mutant BL21∆luxS did not produce endogenous AI-2, no AI-2 could be released from the recombinant LsrB (BL21∆luxS). The combination of endogenous AI-2 produced by BL21 (DE3), which is known to interfere with the binding of AI-2 to LsrB (BL21), resulted in the loss in the ability of LsrB (BL21) to bind to exogenous AI-2. Hence, the BL21 (DE3) luxS mutant, which was incapable of producing endogenous AI-2, but could bind to exogenous AI-2