Investigating the influence of ionic concentrations and subunit interactions on the self-assembly of E2 protein
Tan, Sze Wah
Dharmawan, Ratna Ekawati
Date of Issue2012
International Conference on Nanotechnology - Research and Commercialization (2011 : Sabah, Malaysia)
School of Chemical and Biomedical Engineering
Understanding of self-assembly mechanism of viruslike protein cage is important in controlling release of molecular cargo for applications in drug delivery. E2 core protein is composed of 60 subunits which self-assemble into a hollow 25-nm porous protein cage. Due to its virus like dodecahedral structure without infectious capacity, we are interested in its potential application as nanocapsule in drug delivery. In our study, extrinsic and intrinsic factors that influence self-assembly were evaluated. Extrinsic factors, such as salts and denaturants, were introduced into E2 protein solution. The hydrodynamic diameter of the E2 core protein was used to monitor its disassembly or aggregation. We found that the protein size increased proportionally with the salt concentration while the size decreased as the denaturant concentration increased. To assess intrinsic factors that influence E2 self-assembly, we identified some key amino acids at interfaces of subunits and performed site-directed mutagenesis on them. Characterizations of each mutant for size and secondary structure contents were performed. We found that mutations at the inner surface have no apparent effects on both protein sizes and secondary structures. The mutations at intra-trimer interfaces changed the secondary structure contents but the protein sizes remained stable.
© 2012 American Institute of Physics. This paper was published in International Conference on Nanotechnology - Research and Commercialization 2011 and is made available as an electronic reprint (preprint) with permission of American Institute of Physics. The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4769132]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.