Objective  Functions of ZmCOL3 involving the flowering regulation and other mechanisms in maize were investigated by analyzing the structure and functions of the protein encoded by the gene.

  Method  Based on bioinformatics, the physicochemical properties, conserved domain, secondary and tertiary structures, signal peptide, transmembrane domain, subcellular localization, and cis acting elements of ZmCOL3 protein were predicted. Expression of the gene in various organs of a maize plant were analyzed.

  Result  The ZmCOL3-encoded protein contained 335 amino acids with a molecular weight of 35.39 KD and a theoretical isoelectric point of 5.04. It was an unstable acidic, hydrophilic protein located primarily in the nucleus and consisted of a CCT domain and a B-box domain but no signal peptide or transmembrane domain. Its secondary structure was mostly irregular coils with some α helixes and a small number of extended chains and β turns. The homology modeling similarity was 64.15%. The promoter of ZmCOL3 gene not only contained the basic cis acting elements, such as TATA and CAAT boxes, but also light response elements, such as SP1, as well as hormone response elements, such as abscisic acid and methyl jasmonate. In various tissues, the leaves, followed by the male ears, had the highest and significantly higher expression of ZmCOL3 than the primary roots, internodes, or tassels, while and the seeds the lowest.

  Conclusion  The unstable acidic, hydrophilic ZmCOL3 protein contained CCT and B-box domains consistent with the structural characteristics of COL subfamily in the CCT gene family of which it belonged. It was postulated to participate in the regulation of biological clock that affects maize florescence. The promoter of ZmCOL3 gene contained the elements responding to light and various hormones that suggested a possible involvement on the multiple response network regulating the photoperiod and abiotic stress of a maize plant.