Fungal Peptides

Most peptide antibiotics have been isolated from Jictinomycetes and especially from Streptomjces. Many P-lactams, however, and a few other useful peptide antibiotics have come from fungi. These streptomycete and fungal peptide antibiotics include many stmctural types having varied therapeutic indications and/or scientific appHcations. 

The seeds and vegetative part of plants contain several sorts of inhibitors of insect, fungal, mammalian, and endogenous proteinases. These inhibitors may be involved in plant defense mechanisms against predators and participate in the development of the plant itself. Peptidic proteinase inhibitors are well studied in the families Fabaceae, Poaceae, Asteraceae, and Solanaceae (37). Non-proteinaceous inhibitors of serine... 

While many sulfur-containing fungal secondary metabolites are known, they are found less frequently than in plants. There is a structural range from CH2S6, 1,2,3,4,5,6-hexathiapane, from Lentinus edodes, to C82Hii4N2oOi7S, a 13-unit peptide containing methionine from Saccharomyces cerevesiae,13... 

Whereas standard proteases use serine, cysteine, aspartate, or metals to cleave peptide bonds, the proteasome employs an unusual catalytic mechanism. N-terminal threonine residues are generated by self-removal of short peptide extensions from the active yS-subunits and act as nucleophiles during peptide-bond hydrolysis [23]. Given its unusual catalytic mechanism, it is not surprising that there are highly specific inhibitors of the proteasome. The fungal metabolite lactacystin and the bacterial product epoxomicin covalently modify the active-site threonines and in-... 

As is clear from the preceding discussion, plants express a vast array of toxic peptides in their defense that are interesting as structural models, active compounds in crop protection, and active compounds in pharmaceutical applications. In the plant kingdom the defense mechanisms involved have produced peptides for many kinds of microorganisms and predators, and in future it is possible that for any new problem in bacterial, viral, or fungal infection, a solution can be found on the basis of leads from plant defense molecules. 

The structures of the complexes of argifin and argadin with ChiB allowed a comparison with the GlcNAcs complex and description of the nature of mimicry in this system [166]. Figure 13 shows the chemical structures of these cyclic peptides, which were isolated from fungal cultures [168,169]. 

Tanaka A et al., A symbiosis expressed non-ribosomal peptide synthetase from a mutualistic fungal endophyte of perennial ryegrass confers protection to the symbiotum from insect herbivory, Mol Microbiol 57 1036—1050, 2005. 

Kleinkauf, H. von Dohren, H. (1997) Biosynthesis of cyclosporins and related peptides. In Fungal Biotechnology. Anke, T., ed.. Chapman Hall, London, pp. 147-61. 

While trypsin cuts the peptide linkages Lys-X and Arg-X, a fungal protease cleaves only X-Lys.227 A protease from the submaxillary glands of mice cleaves only Arg-X,228 one from Staphylococcus specifically at Glu-X,229/230 and one from kidneys at Pro-X.231... 

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