it to the correct co-ordinates within the asymmetric unit. This is accomplished by moving the model, calculating a new Patterson map, and comparing it to the unknown-derived Patterson map. This brute-force search is computationally expensive and fast translation functions are now more commonly used. Positions with high correlations are output in Cartesian coordinates. Using de novo predicted structures in molecular replacement With the improvement of de novo protein structure prediction, many protocols including MR-Rosetta, QUARK, AWSEM-Suite and I-TASSER-MR can generate a lot of native-like decoy structures that are useful to solve the phase problem by molecular replacement. The next step Following this, we should have correctly oriented and translated phasing models, from which we can derive phases which are (hopefully) accurate enough to derive electron density maps. These can be used to build and refine an atomic model of our unknown structure. References External links Phaser - One of the most commonly used molecular replacement programmes. Molrep - Molecular replacement package within CCP4 Phaser article at PDBe - A helpful public domain introduction to the topic. X-ray crystallography