Single-chain Fv multimers of the anti-neuraminidase antibody NC10: The residue at position 15 in the VL domain of the scFv-0 (VL-VH) molecule is primarily responsible for formation of a tetramer-trimer equilibrium

Abstract

Single-chain variable fragment of the murine monoclonal antibody NC10 specific to influenza virus N9 neuraminidase, joined directly in the VL to VH orientation (scFv-0), forms an equilibrium mixture of tetramer and trimer with the tetramer as the preferred multimeric species. In contrast, the VH-VL isomer was previously shown to exist exclusively as a trimer. Computer-generated trimeric and tetrameric scFv models, based on the refined crystal structure for NC10 Fv domain, were constructed and used to evaluate factors influencing the transition between VL-VH trimer and tetramer. These model structures indicated that steric restrictions between loops spanning amino acid residues L55-L59 and L1..