Protein Expression and Purification, Vol.72, No.2, 162-168, 2010
Cloning, expression and efficient refolding of carbohydrate-peptide mimicry recognizing single chain antibody 2D10
Carbohydrate-peptide mimicry was found to be manifested through the cross-reactivity of an anti-mannopyranoside monoclonal antibody 2D10 (mAb-2D10) with YPY motif containing 12-mer peptide (DVFYPYPYASGS). Such multiple binding options for a monoclonal antibody could emanate from the possible flexibility of the antigen combining site. To address the molecular details of this phenomenon, single chain antibody (scFv) containing the antigen combining variable domain of mAb-2D10 was constructed. The present work describes the cloning, expression, purification and efficient refolding of scFv-2D10 and its His(6) tag fusion variants. The scFv expressed poorly in soluble/active form in the periplasmic compartment and concurrently exhibited higher tendency towards accumulation in inclusion bodies inside the Escherichia coil cytoplasm. The scFv was refolded from the inclusion bodies with 68% yield using a previously described protocol which employed concomitant removal of the chaotropic and oxidizing reagents along with the additives. However, their differential removal, as described in the present report resulted in 97% effective yield of the soluble scFv-2D10, an increase of 42%. The binding kinetics of the refolded scFv for both the mimicking ligands was examined using surface plasmon resonance experiments. The scFv-2D10 exhibited binding affinities similar to those reported for mAb-2D10 (IgG) showing that the modifications introduced in the refolding protocol have facilitated efficient preparation of active 2D10 scFv. (C) 2010 Elsevier Inc. All rights reserved.