Projects on Proteomics and Protein Chemistry

Protein isolation and characterization (by mass spectral analysis and sequencing) is being used to define key defense proteins.  We are particularly interested in a class of small, cysteine-rich proteins (SCRPs) associated with the cell wall.  Being in the apoplast, we believe that the proteins are involved in early definitive interactions with the pathogen.

At the left is the three dimensional structure of defensin, an example of a SCRP. Defensins are antibiotics of great importance in animals as well as plants.

As a class, SCRPs are characterized by the presence of an unusually high number of cysteine residues that form disulfide bonds (see the yellow areas of the defensin protein) and thus make the structures of SCRPs very compact.

There are several other classes of apoplastic SCRPs of interest to us including trypsin inhibitors (pdf file), lipid transfer proteins, snakins and thaumatins.