Understanding the self-assembly mechanism of E2 protein cage and exploring its potential applications
Date of Issue2013
School of Chemical and Biomedical Engineering
Self-assembly protein cages have drawn much attention for their applications in nanotechnology. E2 protein from Bacillus stearothermophilus, which comprises 60 identical subunits to form hollow porous structure, has been demonstrated for being used as nanocapsule in drug delivery. To facilitate future applications such as controlled release, understanding the self-assembly mechanism of E2 protein is considered. We verify that self-assembly of E2 protein is mediated by protein C-terminus using trimer structure as intermediate. Based on understanding the role of inter-trimer interactions, we design pH-responsive E2 protein cages: i) by introducing histidine pairs, mutant protein maintains assembled at physiological pH while dissociates at acidic pH; ii) by substituting C-terminus with GALA peptide, mutant protein dissociates at neutral pH while assembles at acidic pH. To further explore functionalities of the E2 protein, iron-binding peptides are incorporated into the interior surface. The mutant E2 protein is capable of working as a size- and shape- constrained nano-reactor for iron biomineralization.