Team:XJTLU-CHINA/PeptideProduction
Peptide Production
Anti-Microbial Peptide
Anti-microbial peptide (AMP) is a part of the innate immune system of most multi-cellular organisms to counter microbial infections (Margitta and Torsten, 1999). The cationic and amphipathic α-helix structure is the most wildly conformation in those peptides but some hydrophobic α-helical peptides which possess antimicrobial activity. This year we choose three different cationic antimicrobial peptides which encompass α-helical conformation in our project.
Figure 1 shows the molecular mechanism of cationic AMPs α-helical structure. Most of cationic AMPs associate with lipid group of bacteria membrane. The α-helical structure disrupt the packing of lipid molecules such that the membrane becomes leaky (Rocca et al., 1999).
LL-37
LL-37 is the only cathelicidin-derived antimicrobial peptide found in humans (Dürr, Sudheendra and Ramamoorthy, 2006). Mature LL-37 has 37 amino acid residues starting with two leucines (NH2-LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES-COOH). The peptide is cleaved from a larger protein, hCAP-18 by extracellular proteolysis of proteinase 3 from the C-terminal end of hCAP18 (Patricia, 2010; Ramos, Domingues, and Gama, 2011). The peptide composed of two mainly parts: from residue Leu2 to Leu31 is α-helical structure (Fig 2b) and 6 residues form loop structure (Fig 2a).
Ramos, Domingues, and Gama (2011) also reported that LL-37 has additional roles such as regulating the inflammatory response to wound or infection sites, binding and neutralizing LPS, and wound closure apart from anti-microbial property (Figure 2c).
