Epidermin is a large peptide antibiotic, which is synthesized in the ribosome via a precursor protein, followed by enzymatic modifications. It was isolated from the culture filtrate of Staphylococcus epidermidis TU 3298 by adsorption on Amberlite XAD-8. The basic heneicosapeptide amide was chromatographed on Sephadex LH-20 and purified to homogeneity via multiplicative counter-current distributions in one acidic and one neutral system. Tryptic digestion gave the soluble N-terminal fragment epidermin-(I -13)-peptide (Pl) and the insoluble Cterminal fragment 2-oxobutyryl-epidermin-(l5 -21)-peptide amide (P2), each possessing two sulfide ring systems. The heterodetic rings consisted of meso-lanthionine and (2S,3S,6R)-3-methyllanthionine (Pl), meso-lanthionine and C-terminally the new amino acid S-(2-aminovinyl)-~-cysteine (P2). The complex sequence was elucidated via a combination of desulfurization with Raney nickel, enzymatic and acidolytic degradations, gas-phase sequencing, fast-atom bombardment and field-desorption mass spectrometry and NMR spectroscopy.

A decosapeptide that is highly effective against acne has been isolated from a culture filtrate of Staphylococcus epidermidis Tü 3298. The molecule contains four disulfide bridges derived from meso‐lanthionine, β‐methyllanthionine, and the newly discovered amino acid S‐(2‐aminovinyl)‐D‐cysteine. The structure elucidation was achieved by enzymatic and hydrolytic fragmentation and desulfurization with Raney nickel followed by sequence analysis.

The 21-peptide amide antibiotic gallidermin is a potential therapeutic against acne disease. It belongs to the class of polycyclic lanthionine and alpha,beta-didehydroamino acids containing polypeptides, which were named "lantibiotics." The structural gene of the recently elucidated lantibiotic gallidermin encodes a precursor peptide containing Ser, Thr, and Cys residues in the C-terminal prolantibiotic part, and an unusually hydrophilic leader peptide. The ribosomally synthesized pregallidermin is posttranslationally modified and processed to a complex peptide antibiotic with four sulfide rings and two unsaturated residues. The complete solution structure of gallidermin was determined in trifluoroethanol: water (95:5) and dimethylsulfoxide by two-dimensional 1H-nmr at 500 MHz, using a combination of double quantum filtered correlated spectroscopy, homonuclear Hartman-Hahn, and nuclear Overhauser enhancement spectroscopy experiments. Using a total number of 152 distance constraints from NOEs and 14 torsional constraints, derived from coupling constants, we obtained a screwlike solution structure of gallidermin. Restrained molecular dynamics simulations yielded a set of five converging structures with an atomic rms difference of 1.7 A for the backbone atoms, not dependent on the starting structure. The spatial structure model is in excellent agreement with the amphiphilic and channel-forming properties of gallidermin on membranes and its tryptic cleavage at the exposed site between residues 13 and 14.

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From a strain of Bacillus subtilis a new antifungal peptidolipid complex of the iturin group was isolated. This antibiotic complex contained six lipophilic j3-amino acids with 3-amino-14-methylpentanoic acid as the predominant component.L-Ser, 1 D-Tyr and a mixture of 2.9 % iso-C, -~-amino acid, 30.7 % n-C14-(3-amino acid, 15% iso-C1,-(3-amino acid, 9 % anteiso-C,,-(3-amino acid, 35.3% iso-C16-/3-amino acid and 4.5 % n-C16-(3-amino acid. The structures of the p-amino acids were determined by combined GLC/MS. FAB mass spectroscopy revealed three M+H+ peaks (1,043, 1,057, 1,071). Iturin AL could be resolved into six components by HPLC whose structures confirm the high amount of long chain (3-amino acids.Cyclic peptidolipidic antibiotics of the iturin group, such as iturin A and iturin C, have been isolated and described by PEYPOUX, DELCAMBE and co-workers1.1,1). Recently the structures of the R-amino acids of iturin A isolated from two different Bacillus subtilis strains were compared by mass spectroscopy and 13C NMR4). These data revealed that iturin A is composed of a constant set of a-amino acids and a collection of 3-amino acids in which the C14 Q-amino acids and C15-p-amino acids predominate. The present investigation, however, shows that there exist B. subtilis strains, which, under identical media and growth conditions, biosynthesize a mixture of homologous peptides in which the C16-ji-amino acids prevail.Fermentation