A novel cDNA sequence encoding a pig leukocyte antimicrobial peptide with a cathelin-like pro-sequence.

It has recently been shown that the precursors of various structurally unrelated leukocyte antimicrobial peptides share similar pro-regions. These, in turn, are highly identical to a cysteine proteinase inhibitor named cathelin, or PLCPI. In this paper we report a novel cDNA sequence of porcine bone marrow origin, encoding a protein characterized by a cathelin-like domain. The putative protein is 147 amino acid residue long, with a calculated mass of 16479 Da and appears to be the precursor of a recently isolated antimicrobial peptide named protegrin PG-2. The unique sequence of the mature PG-2 is located at the C-terminus of the precursor. Similar to the previously reported precursors, both the signal peptide and the pro-sequence of pre-proPG-2 appear highly conserved.