Expression and Purification of Collagen-Like Proteins of Group A Streptococcus.

Prokaryotic proteins with extended collagen domain are found in many bacterial species that are pathogenic to humans and animals. The collagen domain is often fused to additional ligand-binding domains and plays both structural and functional roles in modular "bacterial collagens." Here, we describe the step-by-step expression and purification of the recombinant streptococcal collagen-like proteins, rScl, using the Strep-tag II system. The integrity and structural characterization of recombinant collagen-like proteins is very important for defining their function.