Simultaneous Multiwavelength Anomalous Diffraction (SMAD): an Energy-Dispersive Synchrotron Diffraction Method for Macromolecules

A new synchrotron data acquisition method, simultaneous multiwavelength anomalous diffraction (SMAD), employing a variable bandwidth curved crystal monochromator (polychromator) coupled with an energy-selecting grid plate is described. The SMAD experiment demonstrates the ability to measure reflections at six different wavelengths and their Bijvoet pairs at the same time. On one diffraction image, both the dispersive and Bijvoet information is recorded from a myoglobin crystal for multiwavelength anomalous diffraction (MAD) phasing.