Gallidermin is a new member of the class of lanthionine-containing peptide antibiotics, which are summarized under the common name lantibiotics. The lantibiotic gallidermin is produced by Staphylococcus gallinarum (F16/P57) Tü3928, and it exhibits activities against the Propionibacteria, involved in acne disease. Gallidermin differs from the recently discovered tetracyclic 21-residue peptide antibiotic epidermin only in a Leu/Ile exchange in position 6. The isolation procedures for gallidermin included adsorption directly from the culture broth, ion-exchange chromatography of the amphiphilic and basic polypeptide followed by desalting, and final purification by reversed-phase HPLC. The structural elucidation of the polypeptide containing four thioether bridges involved mainly a combination of automated gas-phase sequencing, thermospray liquid chromatography/mass spectrometry and fast-atom-bombardment mass spectrometry.

Gallidermin is a new member of the class of lanthionine-containing peptide antibiotics, which are summarized under the common name lantibiotics. The lantibiotic gallidermin is produced by Staphylococcus gallinarum (F16/ P57) Tu3928, and it exhibits activities against the Propionibacteria, involved in acne disease. Gallidermin differs from the recently discovered tetracyclic 21 -residue peptide antibiotic epidermin only in a Leu/Ile exchange in position 6. The isolation procedures for gallidermin included adsorption directly from the culture broth, ionexchange chromatography of the amphiphilic and basic polypeptide followed by desalting, and final purification by reversed-phase HPLC. The structural elucidation of the polypeptide containing four thioether bridges involved mainly a combination of automated gas-phase sequencing, thermospray liquid chromatography/mass spectrometry and fast-atom-bombardment mass spectrometry.The number of naturally found peptide antibiotics containing lanthionine is steadily increasing ( [5, 61, 81, pep5 [9] and the new antibiotic gallidermin described here. Typically these heterodet polycyclic polypeptide antibiotics possess a high content of unsaturated amino acids (dehydroalanine, dehydrobutyrine) and thioether amino acids [meso-lanthionine, (2S,3S,6R)-3-methyllanthionine]. Furthermore lysinoalanine, 3-hydroxyaspartic acid and S-(2-aminovinyl)-~-cysteine were found in some members.We propose the common name 'lantibiotics' for this particular type of most interesting compounds, because they are closely related with respect to their biosynthesis, although they are produced by different microorganisms. There are structural genes coding for the ribosomally synthesized prepeptides, which are post-translationally modified and processed; this was demonstrated for the first time for epidermin [lo] and pep5 (unpublished results). The modification of the prepeptides, containing an N-terminal 'leader sequence', involves enzymic dehydration of serine and threonine residues to dehydro-alanine and dehydrobutyrine, and addition of thiol groups of cysteine residues to the unsaturated amino acids to form the intramolecular thioether bridges of mesolanthionine and (2S,3S,6R)-3-methyllanthionine. The leader sequence is cleaved off, and the mature peptide antibiotic is secreted. The enzymes involved and the order of these steps are not yet known.

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The production of the lanthionine-containing polypeptide antibiotics gallidermin from Staphylococcus gallinarum TU 3928 and pep 5 from S. epidermidis 5 is investigated with respect to regulation and stimulation of productivity by media components, optimization of both the media used and the fermentation process and is compared to the production of the lantibiotic epidermin from S. epidermidis TU 3298. Efficient methods for rapid quantification of lantibiotics, optimization of the media and a primary enrichment by adsorption chromatography are reported.

Peptide antibiotics containing lanthionine and 3‐methyllanthionine bridges, named lantibiotics [1], are of increasing interest. A new lantibiotic, gallidermin, has been isolated from Staphylococcus gallinarum. Here we report the isolation of its structural gene which we name gdmA. In all lantibiotics so far studied genetically, three peptides can be formally distinguished: (i) the primary translation product, which we call the prepeptide; (ii) the propeptide lacking the leader sequence and (iii) the mature lantibiotic. Unlike the plasmid‐coded epidermin, gdmA is located on the chromosome. The gdmA locus codes for a 52 amino acid residue prepeptide, consisting of an α‐helical leader sequence of hydrophilic character, which is separated from the C‐terminus (propeptide) by a characteristic proteolytic processing site (Pro−2 Arg−1 Ile1). Although pro‐gallidermin