Sortase-catalyzed in vitro functionalization of a HER2-specific recombinant Fab for tumor targeting of the plant cytotoxin gelonin.

ABSTRACT: We report on the preparation of a new type of immunotoxin via in vitro ligation of the αHer2 antigen binding fragment (Fab) of the clinically-validated antibody trastuzumab to the plant toxin gelonin, employing catalysis by the bacterial enzyme sortase A (SrtA). The αHer2 Fab was fused with the extended SrtA recognition motif LPET↓GLEH 6 at the C-terminus of its heavy chain, thereby preventing interference with antigen binding, while the toxin was equipped with a Gly 2 sequence at its N-terminus, distant to the catalytically active site in the C-terminal region. Site-specific in vitro transpeptidation led to a novel antibody-toxin conjugate wherein gelonin had effectively replaced the Fc region of a conventional (monomerized) immunoglobulin. After optimization of reaction conditions and in

SUBMITTER: Kornberger P 

PROVIDER: S-EPMC3984325 | biostudies-literature | 2014 Mar-Apr

REPOSITORIES: biostudies-literature