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.