Vise Pamela D, Kodali Kishore, Hoe Nancy, Paszczynski Andrzej, Musser James M, Daughdrill Gary W
Department of Microbiology, Molecular Biology, and Biochemistry, University of Idaho, P.O. Box 443052, Life Science South Rm. 142, Moscow, ID 83844-3052, USA.
Protein Expr Purif. 2003 Dec;32(2):232-8. doi: 10.1016/S1046-5928(03)00235-3.
A secreted, hypervariable virulence factor called the streptococcal inhibitor of complement (Sic) has been linked to the reemergence of epidemics due to the human pathogenic bacterium Group A Streptococcus. This paper describes a method for expressing and purifying Sic from an attenuated GAS strain using a chemically defined growth medium. This method was used to label specific amino acid residue types in Sic with forms containing the magnetically active isotope (15)N, at the amide nitrogen. The (15)N-labeling of Sic permits a detailed investigation of the structure and dynamics of the protein using nuclear magnetic resonance spectroscopy. The level of stable isotope incorporation was established using mass spectrometry and nuclear magnetic resonance spectroscopy.
