Carotenoid cleavage dioxygenases (CCDs) are a group of enzymes that catalyze the oxidative cleavage steps from carotenoids to various carotenoid cleavage products. Someccdgenes have been identified and encoded enzymes functionally characterized in many higher plants, but little in cyanobacteria. We performed a comparative analysis ofccdsequences and explored their distribution, classification, phylogeny, evolution, and structure among 37 cyanobacteria. Totally 61 putativeccdsequences were identified, which are abundant inAcaryochloris marinaMBIC 11017, filamentous N2-fixing cyanobacteria, and unicellular cyanobacterialCyanothece. According to phylogenetic trees of 16SrDNAand CCD,ncedandccd8 genes occur later than the divergence ofccd7,apco, andccd1. All CCD enzymes share conserved basic structure domains constituted by a single loop formed with sevenβ-strands and one helix. In this paper, a general framework of sequence-function-evolution connection for theccdhas been revealed, which may provide new insight for functional investigation.
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