ENGINEERING MEMBRANE PROTEINS USING CHEMICAL APPROACHES
We are developing novel methods for engineering membrane proteins of interest such as voltage gated ion channels, GPCRs and transporters.
One of the central challenges in biochemical research is relating the structure of a protein to its biological function. Protein structure-function studies require the ability to modify the protein. Chemical synthesis is a powerful method for protein modification as it facilitates the incorporation of unnatural amino acids and peptide backbone modifications. These substitutions allow the precise modification of the structural and electronic properties of the protein. Further, protein modifications possible using chemical synthesis vastly exceeds the modifications that can be introduced using conventional site directed mutagenesis. Chemical synthesis is therefore a vital asset in protein structure function investigations. However, synthetic and biochemical challenges have limited the application of chemical synthesis to membrane proteins. To overcome these challenges, we are developing new synthetic methodologies and biochemical approaches to allow the general and easy manipulation of membrane proteins using chemical synthesis.
Our present synthetic targets are the ion channels KcsA, NaK and KvAP. Chemical synthesis of these channels is used for the incorporation of unnatural amino acids, peptide backbone modifications and isotopic/fluorescent labels. The synthetic channels are characterized using x-ray crystallography, spectroscopy and electrophysiology. Using this multidisciplinary approach, we are investigating the mechanism of ion selectivity, voltage gating and slow inactivation.