| X-RAY DIFFRACTION |
7.8 |
? |
ENZYME SOLUTION: 10 MG/ML TRPS IN 50 MM BICINE PH 7.8, 1 MM EDTA, 5 MM DITHIOERYTHRITOL, 20 MUM PYRIDOXAL-5'-PHOSPHATE, RESERVOIR SOLUTION: 50 MM BICINE PH 7.8, 5 MM EDTA, 5 MM DITHIOERYTHRITOL, 0.1 MM PYRIDOXAL-5'-PHOSPHATE, 2 MM SPERMINE, 8-12 % PEG 8000, HANGING DROP GEOMETRY IN CONTRAST TO WHAT HAS BEEN IMPLICATED IN THE PUBLICATION ASSOCIATED WITH THIS PDB-ENTRY (WEYAND & SCHLICHTING, BIOCHEMISTRY 38: 16469-16480, (1999)), THE PH OF THE COMPLEX WAS NOT NEUTRAL BUT 5.0-5.2. THEREFORE, THE STRUCTURE WAS RE-DETERMINED AT PH 7.0 (PDB CODE 2RHG) AND ALSO AT PH 9.0 (PDB CODE 2RH9). THIS DATA SHOWS THAT CLOSURE OF LOOP ALPHA-L6 IS CAUSED BY THE LOW PH AND NOT BY BINDING OF IGP |
