Purification, crystallization and preliminary X-ray diffraction study of a recombinant cytokinin oxidase from Zea mays.

Cytokinins are hormones that are involved in plant growth and development. They are irreversibly degraded by cytokinin oxidases/dehydrogenases, flavoenzymes which contain a covalently bound flavine adenine dinucleotide (FAD) cofactor. Cytokinin oxidase from Zea mays (ZmCKO1) was overexpressed in the yeast Yarrowia lipolytica, purified (molecular weight 69 kDa) and crystallized using the hanging-drop method. Crystals belong to the monoclinic space group C2, with unit-cell parameters a = 250.6, b = 50.6, c = 51.5 A, beta = 94.1 degrees. A complete data set has been collected at 100 K to 1.95 A resolution on an X-ray synchrotron source.