Molecular cloning and identification of a novel porcine cathelin-like antibacterial peptide precursor.

A novel clone (C6) encoding the precursor of a 79-residue proline/arginine-rich antibacterial peptide prophenin was isolated from a porcine bone marrow cDNA library. Its deduced N-terminal propart shows 84% identity with cathelin. Additionally, two cathelin isoforms were isolated from peripheral porcine blood and their N-termini sequenced. The sequence of one isoform corresponds to the cathelin sequence, whereas that of the other protein is identical to the propeptide of C6 clone. Western blot analysis of total proteins from porcine and human bone marrow using polyclonal antibodies against cathelin revealed the presence of immunochemically related high molecular mass proteins of about 30 kDa in both samples, whereas low molecular mass proteins of approximately 12 kDa, corresponding to isolated cathelin, were not detected in human bone marrow.