Application of general formulas for the correction of a lattice-translocation defect in crystals of a lentiviral integrase in complex with LEDGF.

The symmetry inherent to many biological macromolecular assemblies has been implicated in a range of crystal pathologies, including lattice-translocation defects (LTDs). Crystals suffering from classic LTDs contain two lattices that are shifted with respect to each other but nonetheless remain within the length of coherent interference. LTD introduces an undesirable intensity modulation into diffraction data, resulting in scrambled or partially scrambled electron densities. In this report, LTD theory is extended and a new general method for determining defect fractions is developed based on the heights of the non-origin peaks observed in native Patterson maps. The application of this method to crystals of lentiviral integrase in complex with its cofactor, where the observed translocation vector does not equal a small integral fraction of a unit-cell edge, is reported and its general application to all classic LTD cases is predicted.