3ul5

Publication Abstract from PubMed

The three dimensional structure of canecystatin-1, a potent inhibitor of cysteine proteases from sugar cane (Saccharum officinarum), has been solved in two different crystal forms. In both cases it is seen to exist as a domain-swapped dimer, the first such observation for a cystatin of plant origin. Size exclusion chromatography and multi-dimensional NMR spectroscopy show the dimer to be the dominant species in solution, despite the presence of a measurable quantity of monomer undergoing slow exchange. The latter is believed to be the active species whilst the domain-swapped dimer is presumably inactive as its first inhibitory loop has been extended to form part of a long beta-strand which forms a double-helical coiled coil with its partner from the other monomer. A similar structure is observed in human cystatin C but the spatial disposition of the two lobes of the dimer is rather different. Dimerization is presumably a mechanism by which canecystatin-1 can be maintained inactive within the plant avoiding the inhibition of endogenous proteases. The structure described here provides a platform for rationally designing specific cysteine protease inhibitors for biotechnological applications. (c) 2012 The Authors Journal compilation (c) 2012 FEBS.

X-ray crystallography and NMR studies of domain-swapped canecystatin-1.,Valadares NF, de Oliveira-Silva R, Cavini IA, de Almeida Marques I, Pereira HD, Soares-Costa A, Henrique-Silva F, Kalbitzer HR, Munte CE, Garratt RC FEBS J. 2012 Dec 14. doi: 10.1111/febs.12095. PMID:23241243^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.