| X-RAY DIFFRACTION |
6.5 |
301 |
THE ENZYME AND SUBSTRATE WERE MIXED
IN EQUIMOLAR AMOUNTS IN A SOLUTION CONTAINING 50 MM MES PH
5.5, 1.5 MM EDTA. THE COMPLEX WAS FORMED BY INCUBATING THE
MIXTURE AT 95C FOR 2 MIN., THEN AT 65C FOR 2 MIN., AND FINALLY
AT 27C FOR 5 MIN. 1 MM MGCL2 WAS INCLUDED IN THE MIXTURE
BEFORE THE FINAL INCUBATION STEP. A 10 MG/ML CONCENTRATION OF
RNA WAS USED FOR THE CRYSTALLIZATION EXPERIMENTS. THE
RESERVOIR SOLUTION CONTAINED 0.5M (NH4)2SO4, 100 MM MES PH
6.5, AND 35% PEG 3350. AFTER MIXING THE RESERVOIR SOLUTION,
THE SALT AND PEG PHASES WERE ALLOWED TO SEPARATE, AND ONLY THE
SALT PHASE WAS USED FOR THE DROPS. THE CRYSTALS GREW IN
HANGING DROPS OF 2 MICROLITERS AFTER 12 MONTHS OF INCUBATION
AT 28C. THE CRYSTALS WERE WASHED IN THE SALT PHASE OF THE
RESERVOIR SOLUTION PRIOR TO CRYO-FREEZING, VAPOR DIFFUSION, HANGING DROP, temperature 301K |
