Peptide antibiotics cyclic

Bacitracin (Fig. 4) is a cyclic peptide antibiotic. The lipid II molecule involved in the bacterial cell wall biosynthesis has a C55 isoprenyl pyrophosphate moiety that must be dephosphorylated so that it can reparticipate in another round of lipid II transfer. Bacitracin binds to the isoprenyl pyrophosphate and prevents the dephosphorylation which, in turn, blocks cell wall growth by interfering with the release of the muropeptide subunits to the outside of the bacterial cell membrane. Bacitracin inhibits similar reactions in eukaryotic cells. So, it is systemically toxic but is an effective and widely used topical antibiotic. 

Berninamycinic acid is one of the products from acid hydrolysis of the cyclic peptide antibiotic berninamycin A, which is a potent inhibitor of bacterial protein synthesis. Berninamycinic acid has been assigned the structure (524), anhydro-3,8-dicarboxy-6-hydroxythiazolo[2,3-/][l,6]naphthyridin-4-ium hydroxide. The 6-hydroxy group arises during hydrolysis from a peptide-bonded amino group (77JA1645). 

Bacitracin is a basic cyclic peptide antibiotic consisting of more than 20 components, but, except for the major components BC-A and BC-F, the chemical structures of other components are still unknown. 

GR 159897 is an indolylpiperidine, a TACHYKININ RECEPTOR ANTAGONIST selective for the NK -receptor subtype. It shows ANXIOLYTIC properties in animal models, gramicidin S [inn] is a (cyclic peptide) antibiotic. Active as an antibacterial and used clinically topically against Gram-positive bacteria. 

After the Second World War, the effort continued to find other novel antibiotic structures. This led to the discovery of the peptide antibiotics (e.g. bacitracin (1945)), chloramphenicol (Fig. 10.72) (1947), the tetracycline antibiotics (e.g. chlortetracycline (Fig. 10.71) (1948)), the macrolide antibiotics (e.g. erythromycin (Fig. 10.73) (1952)), the cyclic peptide antibiotics (e.g. cycloserine (1955)), and in 1955 the first example of a second major group of (3-lactam antibiotics, cephalosporin C (Fig. 10.41). 

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... 

Cyclic peptide antibiotics produced by bacteria of Bacillus genus 01KPS103. 

R. Kohli, C. Walsh, M. Burkart, Biomimetic synthesis and optimization of cyclic peptide antibiotics, Nature 2002, 418,658-661. 

Bicozamydn. Bicydomycin aizumycin 8,10-di-aza -6-hydroxy -5 -methylene -1 -(2-methyl -1,2,3 -trihydroxy -propyl)-2-oxabicycln[4.2.2]decan-7,9-dione antibiotic 5879 WS-4545 antibiotic Bacteron Bacfeed. CuHtlN207 mnl wt 302.28. C 47.68%, H 6.00%, N 9.27%, O 37.05%. Cyclic peptide antibiotic substance. Prepn by fermentation ol Streptomyces sapparvnsis T. Miyoshi et al., Gcr. pat. 

As Figure 10 shows, the pulse sequence of Figure 11 with the phase cycling scheme [13] can give 2D spectra that are quite clean and easy to interpret. The spectrum of Figure 10, for an aqueous solution of the cyclic peptide antibiotic viomycin, summarizes all the coupling and connectivity information that would be obtained from a complete series of homonuclear double resonance experiments. A similar spectrum is discussed in more detail in reference 52. 

At Hofmann-La Roche the work of K. Vogler and R.O. Studer on cyclic peptide antibiotics, for instance the polymyxins, is particularly noteworthy. At SANDOZ, R.A. Boissonnas was the primary mover of peptide studies. His work on mixed anhydrides (cf. p. 81) was the starting point of a continued research effort in which S. Guttmann, J. Pless. E. Sandrin, R. Huguenin, P.A. Jaquenoud, H. Bossert, W. Bauer and several younger associates participated. After early syntheses of the hormones of the neurohypophysis they became leaders in the synthesis of biologically active peptides on an industrial scale and first made oxytocin, then more complex molecules such as salmon calcitonin or more recently a cychc peptide with somatostatin activity, commercially available. 

Cyclic peptide antibiotic. Prod, by Stachybotrys chartarum. Immunosuppressant. Powder + IH2O. Mp 156-158°. [a]p —230 (c, 1 in CHCI3). Related to Cyclosporins, C-02421. 

Cyclic peptide antibiotic. Prod, by Streptomyces sp. RE-701. Endothelin type B receptor antagonist. Powder. 

Cyclic peptide antibiotic. Prod, by Streptomyces bernensis. Powder. 

Cyclic peptide antibiotic. Constit. of Chassalia parvifolia. Shows HIV-inhibitory activity. Incorrectly indexed in CA. 

Cyclic peptide antibiotic. Constit. of the sponges Phakellia costata and Stylotella aurantium. Cytotoxic. Amorph. solid. Mp 247-249°. [a] -50.5 (c, 0.33 in CHCI3). 

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