Crystallization and preliminary X-ray diffraction analysis of a novel pectate lyase from Azospirillum irakense

The PelA gene from the N(2)-fixing plant-associated bacterium Azospirillum irakense encodes a pectate lyase. Analysis of the corresponding amino-acid sequence revealed no homology to other bacterial, plant and fungal pectinases of known published structure, resulting in the classification of the enzyme in a new pectate lyase family. The A. irakense PelA has been crystallized using the hanging-drop vapour-diffusion method at 277 K. The crystals are hexagonal, with unit-cell parameters a = b = 85.55, c = 230.13 A, gamma = 120 degrees, and belong to space group P6(5)22 or P6(1)22, having one molecule per asymmetric unit. Diffraction data to a resolution of 1.97 A were collected at synchrotron facilities, as well as a three-wavelength MAD data set from an Hg-derivative crystal to a resolution of 2.6 A.