1m4f
Solution Structure of Hepcidin-25
Structural highlights
DiseaseHEPC_HUMAN Defects in HAMP are the cause of hemochromatosis type 2B (HFE2B) [MIM:613313; also known as juvenile hemochromatosis (JH). HFE2B is a disorder of iron metabolism with excess deposition of iron in the tissues, bronze skin pigmentation, hepatic cirrhosis, arthropathy and diabetes. The most common symptoms of hemochromatosis type 2 at presentation are hypogonadism and cardiomyopathy.[1] [2] [3] [4] [5] FunctionHEPC_HUMAN Seems to act as a signaling molecule involved in the maintenance of iron homeostasis. Seems to be required in conjunction with HFE to regulate both intestinal iron absorption and iron storage in macrophages (By similarity).[6] Has strong antimicrobial activity against E.coli ML35P N.cinerea and weaker against S.epidermidis, S.aureus and group b streptococcus bacteria. Active against the fungus C.albicans. No activity against P.aeruginosa.[7] Publication Abstract from PubMedThe antibacterial and antifungal peptide hepcidin (LEAP-1) is expressed in the liver. This circulating peptide has recently been found to also act as a signaling molecule in iron metabolism. As such, it plays an important role in hereditary hemochromatosis, a serious iron overload disease. In this study, we report the solution structures of the hepcidin-20 and -25 amino acid peptides determined by standard two-dimensional (1)H NMR spectroscopy. These small cysteine-rich peptides form a distorted beta-sheet with an unusual vicinal disulfide bridge found at the turn of the hairpin, which is probably of functional significance. Both peptides exhibit an overall amphipathic structure with six of the eight Cys involved in maintaining interstrand connectivity. Hepcidin-25 assumes major and minor conformations centered about the Pro residue near the N-terminal end. Further NMR diffusion studies indicate that hepcidin-20 exists as a monomer in solution, whereas hepcidin-25 readily aggregates, a property that may contribute to the different activities of the two peptides. The nuclear Overhauser enhancement spectroscopy spectra of the hepcidin-25 aggregates indicate an interface for peptide interactions that again involves the first five residues from the N-terminal end. The solution structure of human hepcidin, a peptide hormone with antimicrobial activity that is involved in iron uptake and hereditary hemochromatosis.,Hunter HN, Fulton DB, Ganz T, Vogel HJ J Biol Chem. 2002 Oct 4;277(40):37597-603. Epub 2002 Jul 22. PMID:12138110[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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