title: Spontaneous Isopeptide Bond Formation as a Powerful Tool for Engineering Site-Specific Antibody-Drug Conjugates.
abstract: Spontaneous isopeptide bond formation, a stabilizing posttranslational modification that can be found in gram-positive bacterial cell surface proteins, has previously been used to develop a peptide-peptide ligation technology that enables the polymerization of tagged-proteins catalyzed by SpyLigase. Here we adapted this technology to establish a novel modular antibody labeling approach which is based on isopeptide bond formation between two recognition peptides, SpyTag and KTag. Our labeling strategy allows the attachment of a reporting cargo of interest to an antibody scaffold by fusing it chemically to KTag, available via semi-automated solid-phase peptide synthesis (SPPS), while equipping the antibody with SpyTag. This strategy was successfully used to engineer site-specific antibody-drug conjugates (ADCs) that exhibit cytotoxicities in the subnanomolar range. Our approach may lead to a new class of antibody conjugates based on peptide-tags that have minimal effects on protein structure and function, thus expanding the toolbox of site-specific antibody conjugation.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, 64287 Darmstadt, Germany.|Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Siegmund
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Birgit
authors.initials: B
authors.lastname: Piater
authors.affiliation: EMD Serono Research &Development Institute, Inc., 45A Middlesex Turnpike, Billerica, MA 01821, USA.
authors.forename: Bijan
authors.initials: B
authors.lastname: Zakeri
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eichhorn
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Fischer
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Carl
authors.initials: C
authors.lastname: Deutsch
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Becker
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Toleikis
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Hock
authors.affiliation: Merck KGaA, Frankfurter Straße 250, 64293 Darmstadt, Germany.
authors.forename: Ulrich A K
authors.initials: UA
authors.lastname: Betz
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Kolmar
mesh_terms: D000906:Antibodies / Q000378:metabolism*; D002616:Chemical Engineering; D018796:Immunoconjugates / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D013678:Technology, Pharmaceutical
chemical_list: D000906:Antibodies; D018796:Immunoconjugates; D010455:Peptides; D004364:Pharmaceutical Preparations