The Chemical Synthesis of Knob Domain Antibody Fragments

• DOI: 10.1021/acschembio.1c00472
• Publication Date: 2021-08-18T16:14:00Z
• Authors: Alex Macpherson; James R. Birtley; Robert J. Broadbr...; Kevin Brady; Monika-Sarah E. D...; Yalan Tang; Callum Joyce; Kenneth Saunders; Gregory Bogle; John Horton; Sebastian Kelm; Richard D. Taylor; Richard J. Franklin; Matthew D. Selby; Maisem Laabei; Toska Wonfor; Adam Hold; Phil Stanley; Douangsone Vadysi...; Jiye Shi; Jean van den Elsen; Alastair D. G. La...
• Keywords: Paratope; Native chemical ligation; Single-domain antibody

Cysteine-rich knob domains found in the ultralong complementarity determining regions of a subset bovine antibodies are capable functioning autonomously as 3-6 kDa peptides. While they can be expressed recombinantly cellular systems, this paper we show that also readily amenable to chemical synthesis, with co-crystal structure chemically synthesized domain complex an antigen showing structural equivalence biological product. For drug discovery, following immunization cattle, peptides directly from antibody sequence data, combining power and diversity immune repertoire ability rapidly incorporate nonbiological modifications. We demonstrate that, through rational design non-natural amino acids, paratope massively expanded, case improving efficacy allosteric peptide. As potential route further improve stability, performed head-to-tail cyclizations, exploiting proximity N C termini synthesize functional, fully cyclic fragments. Lastly, highlight stability plasma and, pharmacokinetic studies, use palmitoylation extend half-life vivo. This study presents antibody-derived medicinal chemistry platform, protocols for solid-phase synthesis domains, together characterization their molecular structures, vitro pharmacology, pharmacokinetics.