Creative Biolabs offers the novel APP phage display library construction service for our global clients. The generation of APP library adopts our proprietary Hi-Affi™ phage display platform which can achieve high affinity and diversity.
APP, the acronym for avian pancreatic polypeptide, is a kind of secretory peptide with some hormonal properties that is produced predominantly by the pancreas. Pancreatic polypeptide has been shown to affect the secretion of pancreatic enzymes, water and electrolytes which is of biphasic manner in terms of APP initially enhancing secretion and then inhibiting secretion. In physical activity, APP increases gut motility and gastric emptying, also relaxes the ileocecocolic and pyloric sphincters, gallbladder and the colon. However, the exact physiologic role of APP in healthy individuals is yet to be fully defined.
Based on the structure analysis, APP is a small protein of 36 amino acid residues. It consists of an α-helix (residues 14-31), a type II polyproline helix (residues 1-8) joined by a type I β-turn (residues 9-13), a flexible C-terminal segment (residues 32-36) and lacking disulphide bridges. The two helices lie antiparallel and interact through strong hydrophobic forces. With a cooperative thermal melt mechanism, APP also exhibits a surprisingly stable structure of Tm 60 °C. According to its small size and stability, APP has been considered as an excellent scaffold for protein grafting of α-helical recognition epitopes.
Hi-Affi™ phage display platform is developed by Creative Biolabs to generate high quality scaffold protein phage display library. Phage display technology, which is an exogenous gene expression method through fusing the target genes to bacteriophage coat proteins then displaying on the phage surfaces to select specific binders, is the foundation of Hi-Affi™ phage display platform. Beyond that, this advanced platform also combines trimer codon technology and NNK method which can introduce more randomicity, higher affinity and diversity for the constructed library. Hi-Affi™ phage display platform is special designed for sorting and isolating the high affinity protein or peptide targets. The generated APP phage display library, with this platform, can achieve 100% precise mutant and over 1010 diversity.
Creative Biolabs commits to provide the best library construction service with reasonable price for our global customers. Our professional scientists are confident in generating tailored scaffold protein library with the best quality to facilitate our global clients’ research and project development.
Fig. 1 X-ray analysis (1.4-angstroms resolution) of avian pancreatic polypeptide. (PDB ID: 1PPT)