Antimicrobial Peptides

Countless studies have exhibited the fact that despite growing problems with resistance to antimicrobial agents amongst vital bacterial pathogens, the quantity of new antibiotics have been brought to the market has exposed a quick failure over the past several decades. Moreover, the requirement for alternative therapeutic possibilities as the antimicrobial peptides (AMPs) has become urgent. A complete understanding of the action of AMPs is of highest significance at a time when the first AMP is about to reach the market, both in terms of understanding the penalty of use and the design of improved drugs. The book begins with a short introduction that provides an overview of history, structure, classification and mechanism of action of the AMPs. In this book, AMPs are categorized by their target and mode of action. For natural AMPs, we will emphasis on those from eukaryotes. Part 1 focuses on antivirial AMPs that neutralize viruses by integrating into either the viral envelope or the host cell membrane. It appears to be difficult to predict antiviral activity based on secondary structures of peptides, for this reason are discussed AMPs with different structures as Mellitin (a-helix), Mastoparan (a-helix), Defensin (b-sheet) and Protegrin (b-sheet). Part 2 shows selected examples of natural antibacterial peptides. Antibacterial AMPs are the most studied AMPs and most of them are cationic, which target bacterial cell membranes and cause breakdown of the lipid bilayer structure. As consequence, Part 3 covers AMPs with an antifungal activity which has a unique structure-activity relationship because their sequences tend to be relatively rich in polar and neutral amino acids. Their mode of action was first described as involving either fungal cell lysis or interference with fungal cell wall synthesis. Antiparasitic peptides are a smaller group compared to other three AMP classes and they are the subject of the overview of Part 4. Finally, the last Part 5 focuses on novel strategies for designing of new synthetic AMPs. Clarification of the activity pathways as well as search of correlations between activity and features like hydrophobicity, hydrophilicity, charge, etc., will allow the developing of new artificial AMPs with augmented activity by means of appropriate amino acid replacements.