Essay On Cathelicidins

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Many antimicrobial peptides can be found in different species but among them a few can be isolated from the human. Among them, two are very much important and they are cathelicidins (LL-37) and defensins (alpha and beta).

3.1 Cathelicidin
Cathelicidins are varying in amino acid sequence, structure and size. They range in size from 12-80 amino acid residues and have a wide range of structure (Gennaro R, 2000). About 30 cathelicidin family members have been idenfied in mammalian species but LL-37 is the only one cathelicidin found in human. LL-37 which begins with two leucine residues at its N-terminus, and is 37 a residues long, with a molecular weight of 18 kDa (Gudmundsson GH, 1995). LL-37 is disordered in aqueous solution but can …show more content…

Moreover, it had been found that LL-37 gene expression is influenced by MEK 1/2 and p38 MAPK signaling pathways in A549 cells infected with Mycobacterium bovis bacillus Calmette-Guerin which is a tuberculosis vaccine mostly used in worldwide (Mendez-Samperio P, 2008). As an antiviral agent, LL-37 has been found to give local protection against HIV-1 infection by epithelial expression (Bergman P, 2007). It was found that the immunological response of this peptide has been changed in infected patients with papillomavirus (Conner K, 2002). As an antifungal agent, it is also active against Candida albicans. The activity is depending on the culture condition whether it will effective as a superficial barrier to the invasion (den Hertog AL, 2006) (Lopez-Garcia B, 2005). 3.2 Defensins:
Defensins are also small, cysteine-rich and cationic peptide which are consisting of 18-45 amino acids with 6-8 cysteine residues and they form disulfide bridges. Due to the differences in alignment of disulfide bond and molecular structure, two subclasses can be found in human. They are alpha defensins and beta defensins. Human alpha defensins are also called human neutrophil peptides and have four subtypes such as, HNP1, HNP2, HNP3 and HNP4 which are 29-35 amino acids long. First three subtypes

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