title: Multivalent site-specific phage modification enhances the binding affinity of receptor ligands.
abstract: High-throughput screening of combinatorial chemical libraries is a powerful approach for identifying targeted molecules. The display of combinatorial peptide libraries on the surface of bacteriophages offers a rapid, economical way to screen billions of peptides for specific binding properties and has impacted fields ranging from cancer to vaccine development. As a modification to this approach, we have previously created a system that enables site-specific insertion of selenocysteine (Sec) residues into peptides displayed pentavalently on M13 phage as pIII coat protein fusions. In this study, we show the utility of selectively derivatizing these Sec residues through the primary amine of small molecules that target a G protein-coupled receptor, the adenosine A1 receptor, leaving the other coat proteins, including the major coat protein pVIII, unmodified. We further demonstrate that modified Sec-phage with multivalent bound agonist binds to cells and elicits downstream signaling with orders of magnitude greater potency than that of unconjugated agonist. Our results provide proof of concept of a system that can create hybrid small molecule-containing peptide libraries and open up new possibilities for phage-drug therapies.
authors.forename: Jaymes
authors.initials: J
authors.lastname: Beech
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Lana
authors.initials: L
authors.lastname: Saleh
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Julie
authors.initials: J
authors.lastname: Frentzel
authors.forename: Heidi
authors.initials: H
authors.lastname: Figler
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Corrêa
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Brenda
authors.initials: B
authors.lastname: Baker
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Caroline
authors.initials: C
authors.lastname: Ramspacher
authors.forename: Melissa
authors.initials: M
authors.lastname: Marshall
authors.forename: Siva
authors.initials: S
authors.lastname: Dasa
authors.affiliation: ⊥La Jolla Institute for Allergy and Immunology, La Jolla, California 92037, United States.
authors.forename: Joel
authors.initials: J
authors.lastname: Linden
authors.affiliation: #Division of Chemical Biology, New England Biolabs, Ipswich, Massachusetts 01938, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Noren
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Kelly
mesh_terms: D000818:Animals; D017104:Bacteriophage M13 / Q000378:metabolism*; D001665:Binding Sites / Q000502:physiology; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans; D008024:Ligands; D011485:Protein Binding / Q000502:physiology; D043682:Receptor, Adenosine A1 / Q000378:metabolism*
chemical_list: D008024:Ligands; D043682:Receptor, Adenosine A1