Crystallization, X-ray diffraction analysis and SIRAS phasing of human α-<scp>L</scp>-iduronidase

Human lysosomal α-L-iduronidase, whose deficiency causes mucopolysaccharidosis type I, was crystallized using sodium/potassium tartrate and polyethylene glycol 3350 as a precipitant. Using synchrotron radiation, a native data set was collected from a single crystal at 100 K to 2.3 &#197; resolution. The crystal belonged to space groupR3 with unit-cell dimensions ofa=b= 259.22,c= 71.83 &#197;. To obtain the phase information, mercury-derivative crystals were prepared and a single-wavelength anomalous dispersion (SAD) data set was collected at the Hg peak wavelength. Phase calculation with the single isomorphous replacement with anomalous scattering (SIRAS) method successfully yielded an interpretable electron-density map.