Isolation and characterization of an IgNAR variable domain specific for the human mitochondrial translocase receptor Tom70

Abstract

The new antigen receptor (IgNAR) from sharks is a disulphide bonded dimer of two protein chains, each containing one variable and five constant domains, and functions as an antibody. In order to assess the antigen-binding capabilities of isolated IgNAR variable domains (VNAR), we have constructed an in vitro library incorporating synthetic CDR3 regions of 15-18 residues in length. Screening of this library against the 60 kDa cytosolic domain of the 70 kDa outer membrane translocase receptor from human mitochondria (Tom70) resulted in one dominant antigen-specific clone (V NAR 12F-11) after four rounds of in vitro selection. VNAR 12F-11 was expressed into the Escherichia coli periplasm and pu..