Masound Vedadi
PI, Molecular Biophysics,
University of Toronto
Abstract:
Structural genomics efforts have led to the expression of thousands of proteins,
many of which have not been purified or characterized previously.
Identification of small molecules that bind to and stabilize these proteins can
promote their crystallization as well as provide valuable functional information.
We have employed differential static light scattering (DSLS), differential scanning
fluorimetry (DSF) and isothermal denaturation (ITD) to investigate the thermostability
and ligand binding specificity of our protein targets. Optimum buffer conditions which
further stabilized the aggregating or hard to concentrate proteins often resulted in
more soluble proteins which were further concentrated. Presence of identified ligands
in many cases resulted in crystallizing those hard to crystallize proteins and improving
crystal quality leading to structure determination. Screening different members of
families of proteins against customized libraries of compounds also resulted in binding
profiles for each protein and providing the opportunity to compare small molecule
binding specificity of different members of each family of protein. The screening results
facilitated the comparison of substrate specificities and also identified compounds which
appeared to be general inhibitors for each of these protein families. Moreover, other
compounds were discovered that only bind to a subset of proteins in each family of
proteins and thus appear to discriminate among different members of the family.
