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- Wang, Stephanie X., et al.
(författare)
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The structure of chagasin in complex with a cysteine protease clarifies the binding mode and evolution of an inhibitor family
- 2007
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Ingår i: Structure. - : Elsevier BV. - 0969-2126. ; 15:5, s. 535-543
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Tidskriftsartikel (refereegranskat)abstract
- Protein inhibitors of proteolytic enzymes regulate proteolysis and prevent the pathological effects of excess endogenous or exogenous proteases. Cysteine proteases are a large family of enzymes found throughout the plant and animal kingdoms. Disturbance of the equilibrium between cysteine proteases and natural inhibitors is a key event in the pathogenesis of cancer, rheumatoid arthritis, osteoporosis, and emphysema. A family (142) of cysteine protease inhibitors (http://merops.sanger.ac.uk) was discovered in protozoan parasites and recently found widely distributed in prokaryotes and eukaryotes. We report the 2.2 A crystal structure of the signature member of the 142 family, chagasin, in complex with a cysteine protease. Chagasin has a unique variant of the immunoglobulin fold with homology to human CD8 alpha. Interactions of chagasin with a target protease are reminiscent of the cystatin family inhibitors. Protein inhibitors of cysteine proteases may have evolved more than once on nonhomologous scaffolds.
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