| X-RAY DIFFRACTION |
7.5 |
296 |
ACTIVE F1-ATPASE (12 MG/ML) WAS EXCHANGED ON A DESALTING COLUMN INTO CRYSTALLISATION BUFFER, PREPARED IN D2O CONSISTING OF 100 MM BIS-TRIS PROPANE, PH 7.5, 100 MM SUCROSE, 1 MM ADP AND 10 MM MAGNESIUM SULPHATE. THEN THE ENZYME WAS INHIBITED AT 23C WITH A 4-FOLD MOLAR EXCESS OF YI1-53 (MUTATION E21A) IN THE PRESENCE OF 1 MM ATP AND 2 MM MAGNESIUM SULPHATE. FURTHER PORTIONS (5 UL OF A NEUTRALISED STOCK SOLUTION CONTAINING 200 MM ATP AND 400 MM MAGNESIUM SULPHATE/ML PROTEIN SOLUTION) WERE ADDED AFTER 5 AND 10 MIN. MORE THAN 95% OF THE ATP HYDROLYSIS ACTIVITY OF THE ENZYME WAS INHIBITED. SODIUM-POTASSIUM TARTRATE WAS ADDED TO 100 MM, AND THE CONCENTRATION OF THE PROTEIN SOLUTION WAS ADJUSTED TO 10 MG/ML WITH CRYSTALLISATION BUFFER. CRYSTALS WERE GROWN AT 23C IN 72 WELL MICRO-BATCH PLATES UNDER FILTERED PARAFFIN OIL. THE CRYSTALLISATION DROPS (4 UL) CONTAINED A 1:1 MIXTURE OF PROTEIN SOLUTION AND PRECIPITANT SOLUTION (20%-26% POLYETHYLENE GLYCOL 3000 AND 600 MM NACL PREPARED IN D2O). |
