Expression, crystallization and preliminary X-ray analysis of an anomeric inverting agarase from Pseudoalteromonas sp. CY24.

AgaB from Pseudoalteromonas sp. CY24 is a novel agarase that hydrolyzes agarose to generate products with inverted anomeric configuration and that has been proposed to have a larger catalytic cleft than other β-agarases. Here, the expression, purification, crystallization and data collection of AgaB in both wild-type and selenomethionine-substituted forms is described. The crystals of wild-type AgaB diffracted to 1.97 Å resolution and belonged to space group C222(1). The selenomethionine derivative crystallized in space group I222. The phasing problem was solved by the multiwavelength anomalous dispersion (MAD) method. These results will facilitate detailed structural and enzymatic analysis of AgaB.