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Pharmaceuticals 2014, 7(5), 545-594; doi:10.3390/ph7050545
Review

Human Antimicrobial Peptides and Proteins

Received: 17 January 2014; in revised form: 15 April 2014 / Accepted: 29 April 2014 / Published: 13 May 2014
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Abstract: As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32) can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized medicine to combat drug-resistant superbugs, fungi, viruses, parasites, or cancer. Alternatively, multiple factors (e.g., albumin, arginine, butyrate, calcium, cyclic AMP, isoleucine, short-chain fatty acids, UV B light, vitamin D, and zinc) are able to induce the expression of antimicrobial peptides, opening new avenues to the development of anti-infectious drugs.
Keywords: antimicrobial chemokines; antimicrobial neuropeptides; antimicrobial proteins; cathelicidin LL-37; defensins; dermcidin; hepcidins; histatins; RNases antimicrobial chemokines; antimicrobial neuropeptides; antimicrobial proteins; cathelicidin LL-37; defensins; dermcidin; hepcidins; histatins; RNases
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Wang, G. Human Antimicrobial Peptides and Proteins. Pharmaceuticals 2014, 7, 545-594.

AMA Style

Wang G. Human Antimicrobial Peptides and Proteins. Pharmaceuticals. 2014; 7(5):545-594.

Chicago/Turabian Style

Wang, Guangshun. 2014. "Human Antimicrobial Peptides and Proteins." Pharmaceuticals 7, no. 5: 545-594.



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