Natural antibacterial peptide

The well-defined helical structure associated with appropriately substituted peptoid oligomers (Section 1.6) can be employed to fashion compounds that closely mimic the stracture and function of certain bioactive peptides. There are many examples of small helical peptides (<100 residues) whose mimicry by non-natural ohgomers could potentially yield valuable therapeutic and bioactive compounds. This section describes peptoids that have been rationaUy designed as mimics of antibacterial peptides, lung surfactant proteins, and coUagen proteins. Mimics of HIV-Tat protein, although relevant to this discussion, were described previously in this chapter (Sections 1.3.2 and 1.4.1). 

Several natural alkaloids, peptides, and depsipeptides related to / -amino acids are active antibacterial, antifungal, or cytotoxic compounds (Tables 1.5.1 and 1.5.2). Accordingly, yS-amino acids already have implications within medicinal chemistry as lead structures or as analogs of a-amino acids within peptides or peptidomi-metics. Selected examples have been discussed. 

Putsep, K., Branden, C.I., Boman, H.G., Normark, S. Antibacterial peptide from H. pylori. Nature 398 (1999) 671-672. 

Chitosan, the deacetylated form of chitin, is a plentiful and naturally occurring aminopolysaccharide obtained fl om shellfish and other marine species. Most of the research on applying this to fibers and films has been conducted in Japan and to a lesser extent Korea. Micromilled chitosan powder has been blended with rayon fibers, followed by subsequent lamination, to produce a variety of nonwoven fabrics known as Chitopoly. These modified materials were even effective against a methacillin-strain of S. aureus [37], Numerous other publications and patents describe incorporation of chitosan in various forms to produce antimicrobial fibers and polymers. One of the more recent examples is the binding of a quaternary ammonium derivative of chitosan to cotton fabric to produce an antibacterial finish [38]. The other area of current interest is the use of naturally occurring peptides as antimicrobial agents. The use of combinatorial libraries allows one to systematically examine ten to hundreds of millions of peptides for their antimicrobial activity. This was demonstrated with various strains... 

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