title: Chemical and genetic wrappers for improved phage and RNA display.
abstract: An Achilles heel inherent to all molecular display formats, background binding between target and display system introduces false positives into screens and selections. For example, the negatively charged surfaces of phage, mRNA, and ribosome display systems bind with unacceptably high nonspecificity to positively charged target molecules, which represent an estimated 35% of proteins in the human proteome. Here we report the first systematic attempt to understand why a broad class of molecular display selections fail, and then solve the underlying problem for both phage and RNA display. Firstly, a genetic strategy was used to introduce a short, charge-neutralizing peptide into the solvent-exposed, negatively charged phage coat. The modified phage (KO7(+)) reduced or eliminated nonspecific binding to the problematic high-pI proteins. In the second, chemical approach, nonspecific interactions were blocked by oligolysine wrappers in the cases of phage and total RNA. For phage display applications, the peptides Lys(n) (where n=16 to 24) emerged as optimal for wrapping the phage. Lys(8), however, provided effective wrappers for RNA binding in assays against the RNA binding protein HIV-1 Vif. The oligolysine peptides blocked nonspecific binding to allow successful selections, screens, and assays with five previously unworkable protein targets.
authors.affiliation: Department of Chemistry, University of California, Irvine, 1102 Natural Sciences 2, Irvine, CA 92697-2025, USA.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Lamboy
authors.forename: Phillip Y
authors.initials: PY
authors.lastname: Tam
authors.forename: Lucie S
authors.initials: LS
authors.lastname: Lee
authors.forename: Pilgrim J
authors.initials: PJ
authors.lastname: Jackson
authors.forename: Sara K
authors.initials: SK
authors.lastname: Avrantinis
authors.forename: Hye J
authors.initials: HJ
authors.lastname: Lee
authors.forename: Robert M
authors.initials: RM
authors.lastname: Corn
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Weiss
mesh_terms: D000595:Amino Acid Sequence; D017104:Bacteriophage M13 / Q000737:chemistry / Q000235:genetics; D001435:Bacteriophages / Q000737:chemistry / Q000235:genetics; D003851:Deoxyribonucleases / Q000737:chemistry / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D008024:Ligands; D008239:Lysine / Q000737:chemistry; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019151:Peptide Library; D011485:Protein Binding; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D054320:vif Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000235:genetics
chemical_list: D008024:Ligands; D019151:Peptide Library; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus; D003851:Deoxyribonucleases; D008239:Lysine