The pMAMPF3-PSTI4 vector encodes a variation of the hPSTI protein (human Secretory Pancreatic Trypsin Inhibitor). hPSTI presents the hypervariable amino acid loop in MoBiTec’s pSKAN Phagemid Display System. The pMAMPF3-PSTI4 can be utilized to produce a soluble hPSTI protein with the desired binding characteristics.
For the process outlined above, the DNA sequence of the hPSTI loop in pMAMPF3 must be exchanged by the sequence of the phage selected during the pSKAN system panning procedure. It is advisable to cleave pSKAN as well as pMAMPF3 at the unique recognition sites of the restriction enzymes Sal I and Kpn I. The resulting 174 bp fragment is easy to clone and includes the amino acid loop of interest. The PSTI4 expressed by pMAMPF3-PSTI4 can serve as a control during the size selection of the recombinant protein with the amino acid loop.