Figure 4

Quantificational detection of surface-displayed GFP-LcsB fusion proteins. (A) Different amounts of purified GFP-LcsB were added to an equal amount of SDS-pretreated and nonpretreated Lb. brevis cells for 1 hour, respectively. Subsequently, the cells were collected, washed and resuspended in 1 mL PBS. 100 μL samples were added to the test plate to measure the fluorescence and cell density at 600 nm, respectively. (B) Standard curve of the fluorescence and the protein concentration of GFP-LcsB fusion protein. The data points represent the averages and standard deviations from four independent experiments.