A 2431-bp full-length cinnamate 4-hydroxylase gene, BoC4H, was cloned from Brassica oleracea L. var. acephala DC.. It contains 2 introns. Its mRNA is 1715 bp, encoding a deduced 481-amino-acid polypeptide with wide homologies to C4Hs from other plants. It possesses cytochrome P450 conserved domains and motifs such as the haem-iron binding motif, the E-R-R triad, the T-con-taining binding pocket motif and the hinge motif neces-sary for optimal orientation of the enzyme. It also has most of the canonical C4H/CYP73A5-featured sub-strate-recognition sites (SRSs) and active site residues. However, owing to a single-base deletion at C2242 and subsequent frame shift within the 3' coding region as com-pared with C4H genes from Arabidopsis thaliana and other plants, BoC4H shows a 36-aa deletion/variation at its C-terminus and the SRS6 motif together with active site residues therein are absent. Thus BoC4H may be of no function or low activity. BoC4H is a membrane protein and is probably associated with the endoplasmic reticu-lure. Its secondary structure is dominated by alpha helices and random coils. The Swiss-Model could not predict its tertiary structure. B. oleracea contains a C4H gene family with at least 5 members.
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