Crystal structures of the free and sterol-bound forms of beta-cinnamomin

The crystal structure of the elicitin h-cinnamomin (h-CIN) was determined in complex with ergosterol at 1.1 A° resolution. h-CIN/ergosterol complex crystallized in the monoclinic space group P21, with unit cell parameters of a =31.0, b =62.8, c =50.0 A° and b =93.4- and two molecules in the asymmetric unit. Ligand extraction with chloroform followed by crystallographic analysis yielded a 1.35 A° structure of h-CIN (P43212 space group) where the characteristic elicitin fold was kept. After incubation with cholesterol, a new complex structure was obtained, showing that the protein retains, after the extraction procedure, its ability to complex sterols. The necrotic effect of h-CIN on tobacco was also shown to remain unchanged. Theoretical docking studies of the triterpene lupeol to h-CIN provided an explanation for the apparent inability of h-CIN to bind this ligand, as observed experimentally. D 2005 Elsevier B.V. All rights reserved.

Keywords

Elicitin Sterol carrier protein Crystal structure Phytophthora

URI

http://hdl.handle.net/10400.1/1224

Citation

Rodrigues, Maria Luisa; Archer, Margarida; Martel, Paulo; Miranda, Sandra; Thomaz, Mónica; Enguita, Francisco J.; Baptista, Ricardo P.; Melo, Eduardo P.; Sousa, Nelson; Cravador, Alfredo; Carrondo, Maria A. Crystal structures of the free and sterol-bound forms of beta-cinnamomin. Biochimica et Biophysica Acta, 1764, 1, 110-121, 2006.

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