Peptide bacteria producing antibiotics from

Cationic peptides were traditionally isolated from natural sources or synthesized fay solid phase or solution phase chemistry. Moreover, they have recently been synthesized by recombinant DNA methods in bacteria (1). insect cells (2), and plants (3,4). The hta that cationic peptides are produced naturally by certain bacteria (e.g., see Qiapter 17), as well as the newly discovered ability to synthesize virtually any peptide by recombinant means in bacteria (1), clearly merits the use of the term "antibiotic for these compounds. Thus, cationic peptides represent not only the first new class of antibiotic in the past 30 yeais, but the world s first genetically engineeriitg antibacterials. 

Cepacidines, glycopeptides produced by Burkholderia cepacia. Cepacidines Ai and Aj belong to the class of antifungal peptides derived from bacteria and fungi. Both peptides display potent antifungal activity for Candida and other species [C. H. Lee et al., J. Antibiot. 1994, 47, 1402]. 

Tyrocidins homodetic, homomeiic, cyclic peptide antibiotics active against Gram-positive bacteria. Like the Gramicidins (see), X are produced by Bacillus brevis. Hie structure of tyrocidin A, confirmed by total synthesis, is cyclo-(-Val-Om-Leu-D-Phe-Pro-Phe-D-Phe-Asn-Gln-IJr-). In tyrocidin B, Phe is replaced by Trp. In tyrocidin C, Phe is replaced by Tip, D-Phc7 by D-Hp, and Asng by Asp. Tyrocidin E differs from tyrocidin A by replacement of Asn by Asp, and Tyrio by Phe. 

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