FIG. 4.

Substrate specificity of purified MBP-AiiM. One microliter of purified MBP-AiiM was mixed with 89 μl of the column buffer (pH 7.4) and 10 μl of 20 mM AHL solution, γ-butyrolactone (γ-BL), or l-homoserine lactone (HSL). After incubation for 1 min, the residual substrate was quantified by HPLC. The activity toward C₁₀-HSL was defined as 100%. The C₁₀-HSL-degrading activity without MBP-AiiM is represented as the control. Filled and open bars represent unsubstituted and 3-oxo-substituted AHLs, respectively. The results were reproduced at least three times, and error bars indicate standard deviations.