This chapter reviews the experiences with the refinement techniques Real Space Refinement (RLSP), COnstrained-REstrained Least-Squares (CORELS) and EREF. From Real Space Refinement experience, several advantages and disadvantages, which are inherent to the method, have been recognized. The principal advantage for improvement of the initial model by fitting to an MIR map lies in the fact that an optimum interpretation of such a map can be obtained before the observed phases are replaced by calculated ones. A new version of CORELS became available, in which the definition of rigid groups especially, and the treatment of different space groups, have been simplified significantly. The main advantages of the Jack–Levitt method became apparent during the refinement of the Protein structures: (1) refinement at low resolution is possible, (2) geometric restraints can be relaxed temporarily, (3) treatment of branched chains is easy, (4) the method requires about 30% less computing time than Diamond's I real space refinement, and (5) distorted geometry can be repaired.
ASJC Scopus subject areas
- Molecular Biology