Schematic of BslA adsorption. When unbound, the conformation of
the hydrophobic cap of WT-BslA (A) orients the hydrophobic residues away
from the aqueous medium, slowing the rate of adsorption (indicated by a
small arrow). The L77K mutation (B) removes the adsorption barrier by exposing
some or all of the hydrophobic residues within the hydrophobic cap,
increasing the rate of adsorption (indicated by a bold arrow). Once adsorbed
onto the interface, the surface-bound WT-BslA refolds to a conformation rich
in β-sheet and is able to form strong lateral interactions with adjacent molecules,
forming an organized lattice that under normal circumstances will not
be removed from the interface (indicated by the crossed arrow). Surfacebound
BslA-L77K forms a less well-organized lattice and can be removed from
the interface with only minimal energy, such as droplet compression.