cDNA cloning of the neutrophil bactericidal peptide indolicidin.

A structurally novel, tryptophan-rich antimicrobial tridecapeptide amide, named indolicidin, has recently been purified from bovine neutrophils (Selsted et al. (1992) J. Biol. Chem. 267, 4292-4295). Here we describe the molecular cloning of this endoantibiotic, which is synthesised in bone marrow cells as a 144 amino acid residue precursor. The encoded protein has a predicted mass of 16479 Da and a pI of 6.51. A putative signal peptide of 29 amino acids precedes a 101 residue pro-region. The mature peptide is at the 3' end of the open reading frame. A glycine, not found in purified indolicidin, is present at the carboxyl terminus of the deduced sequence and is very likely involved in post-translational peptide amidation.