Peptide antibiotic surfactin

Bacillussubtilis produces the cyclic peptide antibiotic surfactin (82).This is an acyl-pep-tidolactone composed of a p-hydroxy fatty acid side chain and seven amino acid residues, including a leucine at position 7. The biosynthesis of surfactin is catalyzed by a peptide synthetase consisting of three modules. The first and second modules are carrying three domains, the last module just one domain. The last domain catalyzes the activation and... 

Figure I Primary structure of bacterial (I) and fungal (II) peptide antibiotics that are synthesized by the noniibosomal thiotemplatc mechanism. (I) (a) gramicidin S, (b) tyrocidine, (c) surfactin. (d) bacitracin (II) (a) HC-toxin, (b) enniatin A. (c) cyclosporin A. The amino acid sequence of the peptides is shown, as are the names of the enzymes that catalyze synthesis. The otder of incorporation is indicated by the anows, beginning with the amino acid shown below the name of the enzyme subunit.

Sen R. Surfactin biosynthesis, genetics and potential apphcations. Adv Exp Med Biol 2010 672 316-23. Heerklotz H, Seelig J. Detergent-like action of the antibiotic peptide surfactin on hpid membranes. Biophys J 2001 81 1547-54. 

Amides and esters are particularly important in biological systems. The phosphate and pyrophosphate derivatives found in DNA and RNA were illustrated in Section 20.12. The structure and chemistry of these compounds will be elaborated upon in Chapter 28. Peptides (discussed in Chapter 27, Section 27.4) are polymers composed of discrete amino acid units. They are joined together by so-called peptide bonds, which are actually amide bonds. Many natural peptides are produced by bacteria via nonribosomal peptide synthesis. Bacillus subtilis produces the heptapeptide surfactin (224), which has antibiotic and antifungal activity. ... 

Eleerklotz El, Seelig J. Detergent-like action of the antibiotic peptide surfactin on hpid membranes. BiophysJ 2001 81 1547-54. 

The B. subtilis lipopeptides are members of a particular antibiotic class formed by surfactin, iturin, and fengycin families. The general structure of these lipopeptides is a peptide cycle of seven (surfactin and iturin) or ten amino acids (fengycin) linked to a fatty add chain. The length of the fatty acid... 

Many of these peptidolipids have amphiphilic properties. This is illustrated by the protoplast-bursting activity of surfactin (93) or by the strong lysing activity of iturin A (but not iturin C) and bacillomycin L on erythrocytes (166), or the disruption of the outer membrane of Escherichia coli by EM 49 (152). Likewise antibiotics of the iturin group increased the size of small unilamellar vesicles of saturated lecithins (167). Differences in the balance between the hydrophobicity of the hydrocarbon chain and the polarity of the peptide moiety might explain the differences of action of iturin A, mycosubtilin and bacillomycin on Micrococcus luteus cells and protoplasts (168). 

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