Interferon alpha 2B
Homo sapiens (human)
Interferons are part of the body's reaction to infections. They do their work through interaction with receptors on the cell surface. More than 15 interferon genes have been identified. Interferon-alpha has found interest as a potential anti-cancer reagent stimulating the immune defense system of the body. The use of interferon has been approved for more than 14 diseases, including cancers and infections like hepatitis.
Interferon occurs naturally as a dimer.The individual monomers of the dimer have a very simple structure made entirely of alpha-helices, reminiscent of membrane-bound proteins. Three alpha-helices line up to form a sheet and two such stacked sheets form one interferon molecule giving the molecule the overall shape of a box. Two such boxes, with their short edges facing each other, form a dimer. The contact between the two monomers within a dimer is not just made by protein-protein interactions, but also involves a zinc ion that is shared by the monomers. The publication accompanying this structure shows that the whole protein structure had been determined. The structure available in the Protein Data Bank however contains only the central atom of each amino acid, the so-called alpha-carbon. In this case the structure was determined by people working for a pharmaceutical company. They hoped that by releasing only incomplete information to make it more difficult for competitors to use this structure for drug development.
Protein Data Bank (PDB)
Radhakrishnan, R. Walter, L.J. Hruza, A. Reichert, P. Trotta, P.P. Nagabhushan, T.L. Walter, M.R.; "Zinc mediated dimer of human interferon-alpha 2b revealed by X-ray crystallography."; Structure; (1996) 4:1453-1463 PubMed:8994971.
author: Arno Paehler