Creative Biolabs provides the best professional service for PBP libraries construction. Through our proprietary Hi-Affi™ platform, an efficient, stable and high affinity scaffold library can be constructed with lower cost compared with the traditional methods.
The periplasmic binding proteins (PBPs), also known as extracellular solute-binding receptors, represent a widely distributed superfamily of proteins which play an important role in chemoreception and transmembrane transport, as well as the initiation of sensory transduction pathways. The solute-binding with integral cytoplasmic membrane proteins is mediated by the hydrophilic solute-binding domains of PBP, with its substantial conformational change to facilitates interaction with the transmembrane chemoreception or transport proteins. Furthermore, PBP is composed of eight classes of bacterial solute-binding proteins specific for: maltooligosaccharides, polysaccharide, α-Glycerol phosphate and iron; hexoses and pentoses; polar amino acids and opines; aliphatic amino acids and amides; peptides and nickel; inorganic polyanions; organic polyanions; iron complexes.
Scaffolds of PBP superfamily, which share conserved structural fold, but high sequence diversity, are valuable sources for protein engineering. In general, PBPs have molecular weights ranging from 23,000 to 41,000 and consist of two domains, which are connected by a hinge region, and a fast reacting and high affinity ligand-binding site, which locates at the interface between the two domains. This binding site can adopt either ligand-free open conformation or ligand-bound closed conformation, which interconvert through a relatively large bending motion around the hinge. In addition, due to the difference of topology by which the polypeptide is distributed between the two domains, PBPs have been divided into two structural subclasses. According to the diversity of biological properties, conformational changes and binding site adaptability, PBP scaffolds are capable to be exploited and engineered for various new functions, such as biosensors, allosteric control elements, biologically active receptors and enzymes.
Creative Biolabs own an advanced Hi-Affi™ phage display platform for constructing PBP scaffold libraries with high affinity and diversity. This platform is based on the original phage display method, 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. In addition, the combination of trimer codon technology and NNK method to this platform has enabled more mutations to further extend the capacity. In general, we can obtain 100% precise mutant with over 1010 diversity for our generated PBP libraries.
Base on the Hi-Affi™ phage display platform, scientists from Creative Biolabs have generated about 55 different types of scaffold libraries for our global clients. With our customer oriented business philosophy, Creative Biolabs is committed to offering the best library construction service to promote our customers’ research and project.
Fig. 1 Periplasmic binding protein structure. (PDB ID: 2LIV)