title: A polystyrene binding target-unrelated peptide isolated in the screening of phage display library.
abstract: Phage display is a powerful methodology for the identification of peptide ligands binding to any desired target. However, the selection of target-unrelated peptides (TUPs) appears as a huge problem in the screening of phage display libraries through biopanning. The phage-displayed peptide TLHPAAD has been isolated both in our laboratory and by another reserach group on completely different screening targets prompting us to hypothesize that it may be a potential TUP. In the current study, we analyzed the binding characteristics and propagation rate of phage clone displaying TLHPAAD peptide (SW-TUP clone). The results of ELISA experiment and phage recovery assay provided strong support for the notion that SW-TUP phage binds to polystyrene with a significantly higher affinity than control phage clones. Furthermore, this polystyrene binding was demonstrated to occur in a concentration- and pH-dependent mode. Characterization of the propagation profile of phage clones within a specified time course revealed no statistically significant difference between the amplification rate of SW-TUP and control phages. Our findings lead us to the conclusion that SW-TUP phage clone with the displayed peptide TLHPAAD is not a true target binder and its selection in biopanning experiments results from its bidning affinity to the polystyrene surface of the solid phase.
authors.affiliation: Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Babak
authors.initials: B
authors.lastname: Bakhshinejad
authors.affiliation: Department of Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran. Electronic address: sadeghma@modares.ac.ir.
authors.forename: Majid
authors.initials: M
authors.lastname: Sadeghizadeh
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019151:Peptide Library; D011137:Polystyrenes / Q000737:chemistry*
chemical_list: D009363:Neoplasm Proteins; D019151:Peptide Library; D011137:Polystyrenes
keywords: Biopanning; Peptide library; Phage display; Polystyrene; TUP