Purification, crystallization and preliminary X-ray analysis of a maize cytokinin glucoside specific beta-glucosidase

Zm-p60.1, a cytokinin glucoside specific beta -glucosidase from maize, is a key enzyme involved in plant development and growth. It has been overexpre ssed in soluble form from Escherichia coli with a His tag at its N-terminus . The recombinant protein has been purified and crystallized at room temper ature using PEG 4000 as the main precipitant. At least three crystal forms have been observed from very similar growth conditions. A flash-annealed mo noclinic crystal diffracted to high resolution (beyond 2 Angstrom) with spa ce group P2(1) and unit-cell parameters a = 55.66, b = 110.72, c = 72.94 An gstrom, beta = 92.10 degrees. The asymmetric unit is estimated and confirme d by molecular-replacement solution to contain one Zm-p60.1 dimer, giving a crystal volume per protein mass (V-M) of 1.89 Angstrom (3) Da(-1) and a so lvent content of 35%.