Cloning, purification, crystallization and 1.57 Å resolution X-ray data analysis of AmsI, the tyrosine phosphatase controlling amylovoran biosynthesis in the plant pathogenErwinia amylovora

The Gram-negative bacteriumErwinia amylovorais a destructive pathogen of plants belonging to the Rosaceae family. Amongst its pathogenicity factors,E. amylovoraproduces the exopolysaccharide amylovoran, which contributes to the occlusion of plant vessels, causing wilting of shoots and eventually resulting in plant death. Amylovoran biosynthesis requires the presence of 12 genes (fromamsA toamsL) clustered in theamsregion of theE. amylovoragenome. They mostly encode glycosyl transferases (AmsG, AmsB, AmsD, AmsE, AmsJ and AmsK), proteins involved in amylovoran translocation and assembly (AmsH, AmsL and AmsC), and also a tyrosine kinase (AmsA) and a tyrosine phosphatase (AmsI), which are both involved in the regulation of amylovoran biosynthesis. The low-molecular-weight protein tyrosine phosphatase AmsI was overexpressed as a His6-tagged protein inEscherichia coli, purified and crystallized. X-ray diffraction data were collected to a maximum resolution of 1.57 Å in space groupP3121.