%0 Journal Article %T Antimicrobial Peptides: Versatile Biological Properties %A Muthuirulan Pushpanathan %A Paramasamy Gunasekaran %A Jeyaprakash Rajendhran %J International Journal of Peptides %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/675391 %X Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries. 1. Introduction The antimicrobial peptides (AMPs) are biologically active molecules produced by wide variety of organisms as an essential component of their innate immune response. The primary role of the AMPs is host defense by exerting cytotoxicity on the invading pathogenic microorganisms, and they also serve as immune modulators in higher organisms [1]. AMPs are considered as a promising and potential drug candidate for the future due to their broad range of activity, lesser toxicity, and decreased resistance development by the target cells [2]. The AMPs were found to exist in a wide range of secondary structures such as ¦Á-helices, ¦Â-strands with one or more disulphide bridges, loop and extended structures. The existences of such diverse structural forms of AMPs are highly essential for their broad spectrum antimicrobial activity [3]. Besides these properties, certain crucial factors such as size, charge, hydrophobicity, amphipathic stereo geometry, and peptide self-association to the biological membrane also attributes for their broad spectrum antimicrobial activity. The smaller size of AMPs facilitates the rapid diffusion and secretion of peptide outside the cells, which is required for eliciting immediate defence response against pathogenic %U http://www.hindawi.com/journals/ijpep/2013/675391/