We perform structural and functional studies of PrtV . For this work, large quantities of pure and soluble protein are
needed. In this study, we address the difficulties of protein domain expression of the PrtV protease by applying a divide and conquer approach. Screening of domain boundaries for individual domains and combinations of domains was carried out, and constructs obtained were further screened for solubility and expression levels. Recombinant PrtV fragments were obtained for three constructs including the N-terminal domain (residues 23–103), the PKD1 domain (residues 755–839), and a longer 25 kDa construct containing part of the M6 domain and PKD1 (residues 581–839) (Fig. 1). The previously described purification procedure for the 81 kDa pro-protein was modified and improved to increase yield and
purity. Interestingly, proteolytic activity measurements of purified
domains suggest that the 37 kDa domain alone is sufficient for protein activity.