Fine-tuning sortase-mediated immobilization of protein layers on surfaces using sequential deprotection and coupling.

Increasing interest in protein immobilization on surfaces has heightened the need for techniques enabling layer-by-layer protein attachment. Here, we report a technique for controlling enzyme-mediated immobilization of layers of protein on the surface using a genetically encoded protecting group. An enterokinase-cleavable peptide sequence was inserted at the N-terminus of bifunctional fluorescent proteins containing Sortase A substrate recognition tags at both ends to control Sortase A-mediated protein immobilization on the surface layer-by-layer. Efficient, sequential immobilization of a second layer of protein using Sortase A required removal of the N-terminal protecting group, suggesting the method enables multilayer synthesis using cyclic deprotection and coupling steps. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:824-831, 2017.