Molecular replacement in P450 crystal structure determinations

Abstract

Publisher Summary This chapter discusses the principle of the molecular replacement (MR) method and the application of this technique to P450 crystal structure determinations. The MR method is used to determine a new protein structure whenever a homologous known structure is available as a search model. MR calculations are essentially the processes of orienting and positioning a model of the known structure in the unit cell of the target protein until a match is found with the unknown protein molecule. Despite the various difficulties in obtaining new P450 structures, the P450 structure database has been growing steadily and has provided essential models for homology modeling, as well as a better pool of search models to aid in solving new P450 structures by the MR technique. However, two similar molecules will generate similar Patterson maps so the trick in the MR technique is to rotate and translate the Patterson of the known structure until it matches the Patterson of the unknown.