Cloning and functional expression of zeta-carotene desaturase, a novel carotenoid biosynthesis gene from Ficus carica
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Abstract
Carotene desaturation, an essential step in the carotenoid biosynthesis pathway, is catalyzed by two enzymes, phytoene desaturase
(PDS) and ζ-carotene desaturase (zeta carotene desaturase, ZDS). Here we describe cloning and E. Coli expression of zds-Fc, a novel
Ficus carica ζ-carotene desaturase catalyzing dehydrogenation of ζ-carotene into neurosporene and finally lycopene. The ζ-carotene desaturase
(ZDS) gene was amplified from the fig tree by rapid amplification of cDNA ends (RACE) and spanned a 1746 bp open reading
frame (ORF), encoding a protein of 582 amino acid residues with a predicted molecular weight of 64kD. The N-terminal region of
this polypeptide contained a putative transit sequence for plastid targeting. By phylogenetic and sequence analyses, zds-Fc showed high
homology with previously described ζ-carotene desaturases from higher plant species (Al-Babili et al. 1998; Cong et al. 2009; Matthews
et al. 2003; Yan et al. 2011). Additionally, sequence analysis revealed a high degree of conservation among plant ZDSs. The deduced
ZDS protein, designated FcZDS, also contains an N-terminus dinucleotide-binding, followed by a conserved region identified in other
carotene desaturase sequences. These data, taken together, confirm our cloned zds-Fc as an integral part of the ZDS family of proteins