The phage display of Bacillus subtilis Lipase A significantly enhances catalytic activity due to altered nanoscale distribution in colloidal solution.

Screening libraries of mutant proteins by phage display is now relatively common. However, one unknown factor is how the bacteriophage scaffold itself influences the properties of the displayed protein. This communication evaluates the effect of solution parameters on the catalytic activity of phage displayed Bacillus subtilis Lipase A (BSLA), compared to the free enzyme in solution. While the pH- and temperature-activity profiles of BSLA were not intrinsically affected by phage display, the nanoscale distribution of BSLA within the micellar assay buffer was. This lead to a pronounced increase of activity of phage-BSLA relative to the free enzyme, owing to the accumulation of phage-BSLA at the substrate-rich micelles. Considering this result obtained for BSLA, caution is warranted and similar effects should be considered when selecting other enzymes/proteins by phage display, as the activity of the displayed protein may differ from that of the free protein.