Controlling protein assembly on inorganic crystals through designed protein interfaces

Area of Science:

• Biomaterials Science
• Protein Engineering
• Surface Chemistry

Background:

• Protein-inorganic surface interactions are crucial for biological functions.
• Highly charged proteins with carboxylic acid side chains mediate these interactions.
• The precise structure of most protein-inorganic interfaces remains largely unknown.

Purpose of the Study:

• To systematically design structured protein-mineral interfaces.
• To engineer proteins that geometrically match inorganic crystal lattices.
• To explore self-assembly of designed proteins on mineral surfaces.

Main Methods:

• Designed proteins with arrays of carboxylate residues to match the potassium ion (K+) sublattice on muscovite mica.
• Investigated protein binding at varying K+ concentrations to observe self-assembly.
• Incorporated designed protein-protein interactions to create extended structures.

Main Results:

• Proteins selectively bound to mica in designed orientations at low K+ concentrations.
• At high K+ concentrations, proteins formed 2D liquid-crystal phases, creating ordered arrays.
• Designed protein-protein interactions led to self-assembled wires and honeycomb arrays with tunable spacing.

Conclusions:

• Protein-inorganic lattice interactions can be systematically programmed.
• This work provides a foundation for designing novel protein-inorganic hybrid materials.
• Precise control over self-assembly at the nanoscale was achieved.