Correction of X-ray intensities from an HslV–HslU co-crystal containing lattice-translocation defects

Because of lattice-translocation defects, two identical but translated lattices can coexist as a single coherent mosaic block in a crystal. The observed structure in such cases is a weighted sum of two identical but translated structures, one from each lattice; the observed structure factors are a weighted vector sum of the structure factors with identical unit amplitudes but shifted phases. The correction of X-ray intensities from a single crystal containing these defects of the hybrid HslV–HslU complex, which consists of Escherichia coli HslU and Bacillus subtilis HslV (also known as CodW), is reported. When intensities are not corrected, a biologically irrelevant complex (with CodW from one lattice and HslU from another) is implied to exist. Only upon correction does a biologically functional CodW–HslU complex structure emerge.