PEROXISOMAL MEMBRANE-PROTEIN PMP68 OF MOUSE-LIVER - CLONING OF A CDNAENCOMPASSING THE NUCLEOTIDE-BINDING FOLD AND EPITOPE MAPPING OF MONOCLONAL-ANTIBODIES TO THE EXPRESSED PROTEIN

We have isolated and sequenced a cDNA which encodes 376 amino acids to ward the carboxy-terminus, and encompassing the putative nucleotide bi nding fold, of PMP68 (mouse liver peroxisomal integral membrane protei n of 68 kDa) the major integral membrane protein of mouse liver peroxi somes. The protein sequence predicted from this cDNA shows 97.9% amino acid identity to this same region of rat liver PMP70, a member of the ATP-binding cassette protein superfamily (K. Kamijo, S. Taketani, S. Yokota, T. Osumi, and T. Hashimoto, 1990, J. Biol. Chem. 265, 4534-454 0). The section of the cDNA encoding the hydrophilic and putative cyto plasmic domain of PMP68 was expressed as a recombinant fusion protein in bacteria, Two monoclonal antibodies raised against this protein hav e been epitope-mapped to peptides generated by cyanogen bromide cleava ge of the fusion protein. Antibody 1A4 recognizes a peptide whose sequ ence contains the first motif of the putative nucleotide binding fold of PMP68, and antibody 8F11 recognizes a carboxy-terminal peptide whic h includes the second motif of this nucleotide binding fold. These ant ibodies are expected to be useful in the elucidation of the biological function of this putative membrane transporter. (C) 1995 Academic Pre ss, Inc.