Artificial Cellulosome Complex from the Self-Assembly of Ni-NTA-Functionalized Polymeric Micelles and Cellulases

Polymer-protein core-shell nanoparticles have been explored for enzyme immobilization. This work reports on the development of functional polymeric micelles for immobilizing His(6)-tagged cellulases with controlled spatial orientation of enzymes, resulting in artificial cellulosomes for effective cellulose hydrolysis. Poly(styrene)-b-poly(styrene-alt-maleic anhydride) was prepared through one-pot reversible addition-fragmentation chain-transfer polymerization and modified with nitrilotriacetic acid (NTA) to afford an amphiphilic block copolymer. The self-assembled polymer was mixed with a solution of NiSO4 to form Ni-NTA-functionalized micelles, which could successfully capture His(6)-tagged cellulases and form hierarchically structured core-shell nanoparticles with cellulases as the corona. Because the anchored enzymes are site-specifically oriented and in close proximity, synergistic catalysis that results in over twofold activity enhancement has been achieved.