Structural characterization of streptococcal protein G (GB1)

Rozavsky, SharonOur research focused on production, purification, crystallization and functional characterization of three different mutants of GB1, a small bacterial protein consisting of 56 amino acids. In particular, its methionine, a sulfur containing amino acid, with its role in ligand recognition and protein-protein interaction was our center of attention. For the first time we successfully incorporated selenomethionine in 3 different GB1 mutants (L5M, V29M and V39M) and crystallized them for X-ray crystallographic study of the three dimensional structure of the protein. Our experiments revealed that most crystals were obtained in conditions containing sodium acetate buffer in a pH ranging from 4.7 to 5. If we compare the quality of crystals among three different mutants of GB1 (L5M, V29M and V39M), the best results were obtained from V39M mutant. Crystals were frozen for future data collection by X-ray crystallography.University of Delaware, Department of Chemistry and BiochemistryM.