Re: [ccp4bb] Experimental phasing vs molecular replacement

2018-12-06 Thread Pavel Afonine
Hi, > Any time you do a thought experiment you make a fake-data data set, the > "true" phases and "true" amplitudes become the ones you put into the > simulation process. This is by definition. Is there potential for > circular reasoning? Of course! But you can do controls: > this is so much

Re: [ccp4bb] Experimental phasing vs molecular replacement

2018-12-06 Thread Dale Tronrud
What may be counter-intuitive when looked at in one way may be perfectly expected from another point of view. I look at these maps as the result of a single cycle of steepest descent refinement where the parameters are the density values of the map sampled on the grid. If you start with a map

Re: [ccp4bb] Experimental phasing vs molecular replacement

2018-12-06 Thread James Holton
Sorry for the confusion, I was going for brevity. Any time you do a thought experiment you make a fake-data data set, the "true" phases and "true" amplitudes become the ones you put into the simulation process.  This is by definition.  Is there potential for circular reasoning?  Of course!  Bu

[ccp4bb] new ERC-funded postdoc positions at the Crick Institute

2018-12-06 Thread Alessandro Costa
Dear all, We two new ERC-funded postdoc positions open in our lab at the Francis Crick Institute in central London. We combine high-resolution cryo-EM with time-resolved methods to image eukaryotic chromatin replication as it occurs in a test tube at cellular rates. We have a fully equi

[ccp4bb] JLIGAND OSX issue

2018-12-06 Thread Xavier Brazzolotto
I’ve updated CCP4 to the latest version (7.0.066) My Mac is updated to the latest OS (10.14.1) I’ve installed the latest JAVA version 1.8.0_191 When I try to use jlgand to build a modified residue I obtain the following error message Exception in thread "main" java.lang.ExceptionInInitializerErr

Re: [ccp4bb] Experimental phasing vs molecular replacement

2018-12-06 Thread Phoebe A. Rice
A point I like to make to new trainees trying to solve structures: Model phases from a good model are pretty good, but from a practical viewpoint, if your initial model for molecular replacement is that good, the resulting structure will probably not tell you much you didn't already know (with e

[ccp4bb] AW: [ccp4bb] Experimental phasing vs molecular replacement

2018-12-06 Thread Herman . Schreuder
I think Jacob is right. As long as protein crystals contain about 10% "dark matter"* not accounted for in any model, we cannot fake a "true" electron density map and it is then not surprising that an 2mFo-DFc map is closer to a model-based fake map than a map based on experimental phases. HS *T