Protein Structure at Solid/Liquid Interfaces
I am interested in the structure and behavior of protein molecules at the solid/liquid interface. The behavior of proteins at solid/liquid interfaces is not well understood. The behavior of proteins in response to the presence of solid/liquid interfaces is key to understanding many fundamental, as well as practical processes. Many physiological processes involve the adsorption of a protein molecule or assembly onto a membrane. It is thought that the adsorption of fibrinogen to many biomaterials is a direct cause of thrombosis . The design of materials for use in surgical instruments, implants and contact lenses could benefit from a better understanding the response of protein molecules to various interfaces.
While there are a number of techniques available for the study of large aggregates and thin films of proteins at interfaces, there have been relatively few techniques available for the measurement of single protein molecules at interfaces. The atomic force microscope (AFM) has shown much promise for the imaging of small biological structures, including protein molecules. However, the information obtained by the AFM for these samples suffers from a fundamental limitation of the instrument. The 'convolution' of the probe tip with the structure being imaged has hindered the use of the AFM for biological materials. I helped to develop a technique, using the AFM as a tool for the accurate (i.e. within ~5 angstroms) measurement of molecular dimensions . This technique is called Surface Oriented Molecular Sizing (SOMS). Using only the accurately measured heights of individual protein molecules (adsobed to a solid substrate) and a statistical thermodynamic model, we have shown that we can accuately determine the dimensions of single protein molecules at the solid/liquid interface. Knowing the dimensions of the molecules at the interface gives information that can aid in determining the oligomeric organization of the protein.
JCU has two scanning probe microscopes. Between the two we have capability to do atomic force microscopy (contact, non-contact, and lateral force) and scanning tunnelling microscopy (STM). I am interested in examining various interesting proteins, modification of adsorption substrates as well as denaturation/unfolding dynamics of proteins at the interface. Some of the biochemical work in these projects is done in collaboration with biochemists, such as Dave Mascotti at JCU.
Interested, want to know more? Email me.
1. Feng, L.; Andrade, J. D. In Proteins at Interfaces II, Fundamentals and Applications; Horbett, T. A., Brash, J. L., Eds.; American Chemical Society: Washington D.C., 1995; Vol. 602 ACS Symposium Series; pp 66.
2. Waner, M. J.; Gilchrist, M.; Schindler, M. and Dantus, M. J. Phys. Chem. B, 1998, 102(9) 1649.
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