X-ray crystallography and NMR studies of domain-swapped canecystatin-1.
 

X-ray crystallography and NMR studies of domain-swapped canecystatin-1.

http://www.bionmr.com//www.ncbi.nlm....x_FullText.gif Related Articles X-ray crystallography and NMR studies of domain-swapped canecystatin-1.

FEBS J. 2013 Feb;280(4):1028-38

Authors: Valadares NF, de Oliveira-Silva R, Cavini IA, Marques Ide A, Pereira HD, Soares-Costa A, Henrique-Silva F, Kalbitzer HR, Munte CE, Garratt RC

Abstract
The three-dimensional structure of canecystatin-1, a potent inhibitor of cysteine proteases from sugarcane (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 multidimensional 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, whereas the domain-swapped dimer is presumably inactive, as its first inhibitory loop has been extended to form part of a long ?-strand that 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 kept inactive within the plant, avoiding the inhibition of endogenous proteases. The structure described here provides a platform for the rational design of specific cysteine protease inhibitors for biotechnological applications.


PMID: 23241243 [PubMed - indexed for MEDLINE]



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