E. Psylinakis et al., Isolation and spectroscopic characterization of a recombinant bell pepper hydroperoxide lyase, BBA-MOL C B, 1533(2), 2001, pp. 119-127
Citations number
47
Categorie Soggetti
Biochemistry & Biophysics
Journal title
BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR AND CELL BIOLOGY OF LIPIDS
Fatty acid hydroperoxide (HPO) lyase is a component of the oxylipin pathway
and holds a central role in elicited plant defense. HPO lyase from bell pe
pper has been identified as a heme protein which shares 40% homology with a
llene oxide synthase, a cytochrome P450 (CYP74A). HPO lyase of immature bel
l pepper fruits was expressed in Escherichia coli and the enzyme was purifi
ed and characterized by spectroscopic techniques. The electronic structure
and ligand coordination properties of the heme were investigated by using a
series of exogenous ligands. The various complexes were characterized by u
sing UV-visible absorption and electron paramagnetic resonance spectroscopy
. The spectroscopic data demonstrated that the isolated recombinant HPO lya
se has a pentacoordinate, high-spin heme with thiolate ligation. Addition o
f the neutral ligand imidazole or the anionic ligand cyanide results in the
formation of hexacoordinate adducts that retain thiolate ligation. The str
iking similarities between both the ferric and ferrous HPO lyase-NO complex
es with the analogous P450 complexes, suggest that the active sites of HPO
lyase and P450 share common structural features. (C) 2001 Elsevier Science
BN. All rights reserved.