Dermcidin is a protein with 110 amino acids that in humans is encoded by the DCDgene.[3][4] The full-length protein produces derived peptides as proteolysis-inducing factor (PIF) and other anti-microbialpeptides,[4] secreted by human eccrine sweat glands onto the skin as a part of the innate host defense of the immune system. PIF is involved in muscular proteolysis.[4]
Function
Dermcidin is a secreted protein that is subsequently processed into mature peptides of distinct biological activities. The C-terminal peptide is constitutively expressed in sweat and has antibacterial and antifungal activities. The N-terminal peptide, also known as diffusible survival evasion peptide, promotes neural cell survival under conditions of severe oxidative stress. A glycosylated form of the N-terminal peptide may be associated with cachexia (muscle wasting) in cancer patients.[4]
The C-terminal precursor DCD-1L is a 48 residue peptide that shows partial helicity in solution, as evidenced by the determination of its solution structure by NMR and CD-spectroscopy. The full length precursor is processed by undetermined proteases present in human sweat, to form several shorter peptides that show variable antimicrobial activity, named according to their C-terminal triplet of amino acids and their residue length. One such active peptide is SSL25, which shows a 2-fold increase in activity against E. coli compared to DCD-1L.[5]
The crystal structure of dermcidin has been solved in solution to reveal a hexameric helix-bundle, mediated by Zn ion binding.[6] This is observed to form a tilted channel in membranes under computational examination by molecular dynamics simulations, and one suggested mechanism of antimicrobial action inferred from this observation is by ion gradient decoupling across biological membranes. This is supported by concurrent observations in experimental studies of a voltage dependent depolarization of lipid bilayers.[citation needed]
Cunningham TJ, Jing H, Wang Y, Hodge L (2000). "Calreticulin binding and other biological activities of survival peptide Y-P30 including effects of systemic treatment of rats". Exp. Neurol. 163 (2): 457–68. doi:10.1006/exnr.2000.7390. PMID10833321. S2CID22279800.
Cunningham TJ, Jing H, Akerblom I, et al. (2002). "Identification of the human cDNA for new survival/evasion peptide (DSEP): studies in vitro and in vivo of overexpression by neural cells". Exp. Neurol. 177 (1): 32–9. doi:10.1006/exnr.2002.7979. PMID12429208. S2CID11829104.
Lai YP, Peng YF, Zuo Y, et al. (2005). "Functional and structural characterization of recombinant dermicidin-1L, a human antimicrobial peptide". Biochem. Biophys. Res. Commun. 328 (1): 243–50. doi:10.1016/j.bbrc.2004.12.143. PMID15670776.
Watchorn TM, Dowidar N, Dejong CH, et al. (2006). "The cachectic mediator proteolysis inducing factor activates NF-kappaB and STAT3 in human Kupffer cells and monocytes". Int. J. Oncol. 27 (4): 1105–11. doi:10.3892/ijo.27.4.1105. PMID16142329.
Lee Motoyama JP, Kim-Motoyama H, Kim P, et al. (2007). "Identification of dermicidin in human gestational tissue and characterization of its proteolytic activity". Biochem. Biophys. Res. Commun. 357 (4): 828–33. doi:10.1016/j.bbrc.2007.03.112. PMID17448443.
