Crystallization and preliminary X-ray diffraction studies of Escherichia coli branching enzyme

Branching enzyme catalyzes the formation of the branch points in glycogen and starch by cleavage of the α-1,4 link and its subsequent transfer to the α-1,6 position. This paper reports the crystallization and preliminary structural studies of an amino-terminally truncated branching enzyme from Escherichia coli. High-resolution diffracting crystals were obtained and a complete native data set to a resolution of 2.3 Å was collected. These crystals belong to the P2₁ space group, with unit-cell parameters a = 91.44, b = 102.58, c = 185.41 Å, β = 91.38°. A native data set with 99.6% completeness, an overall R_merge of 0.086 and I/σ(I) of 10.43 was obtained.