Re: [ccp4bb] Offtopic-ish: Ubuntu Laptop

2009-02-20 Thread Tim Gruene
Hi, you should be able to run the programs you mention on any of the mainstream Linux distributions, especially when you are not scared installing some extra bits and pieces. One of the main nuisances I met recently is the requirement of libg2c for Fortran programs compiled with g77 and

Re: [ccp4bb] Van der Waals Interaction Distances

2009-02-20 Thread Nadir T. Mrabet
Hi, This is one table (below) I use to convince my students that Evdw is still negative when R/Rm = 2, where Rm = Ri + Rj. To take into account water screening effect, however, one should consider vdw attraction only while R Rm + 2 x Rw, where Rw is the radius of water. hth, Nadir ** **

[ccp4bb] Importance of low order reflections?

2009-02-20 Thread Richard Gillilan
Several times I have heard that low order (small angle) reflections are more important when solving low-resolution structures. I presume it is more than just a question of obtaining greater number of reflections. Does anyone know why low-order reflections are so important in these

[ccp4bb] Twin refinement - selecting FreeR

2009-02-20 Thread Sabine Schneider
Hi everyone, I got good data to 2.4A on a protein-ligand complex. I want to solve the structure by MR using a model with 45% seq. ID and 55% similarity. Initially the data appeared to be P622 (pointless, selfrotation function etc). Unit cell: 145 145 65, MW protein is 28kDa I prepared the MR

Re: [ccp4bb] Twin refinement - selecting FreeR

2009-02-20 Thread Roberto Steiner
Hi Sabine, If your question is: Is it possible to refine twinned structures with Refmac? My answer is: Yes. Very well. Best wishes, Roberto On 20 Feb 2009, at 16:32, Sabine Schneider wrote: Hi everyone, I got good data to 2.4A on a protein-ligand complex. I want to solve the structure

Re: [ccp4bb] Van der Waals Interaction Distances

2009-02-20 Thread Pius Padayatti
Here is the original article. Distinction between the weak hydrogen bond and the van der Waals interaction Thomas Steiner*a and Gautam R. Desiraju* Chem. Commun., 1998 891-892 On Thu, Feb 19, 2009 at 11:27 PM, Pius Padayatti ppadaya...@gmail.com wrote: Table 1 Numerical data for X–H···Y contacts

Re: [ccp4bb] Twin refinement - selecting FreeR

2009-02-20 Thread Nathaniel Echols
I used phenix to assign the free reflections putting in the twin operators. Doing simulated annealing in phenix, I get a rather large difference in R/Rfree of ~7%. Well, I guess I need to do some tweaking of the parameters in phenix (running the latest phenix and cci_apps). When I than use

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread Bruno Klaholz
Dear Richard, the low resolution reflections are important for any data set, whether this is a high or medium resolution data set: they describe features corresponding to the size and global position of the crystallized molecule. That's why they are important for molecular replacement, for

[ccp4bb] ARP/wARP and computer platforms

2009-02-20 Thread Victor Lamzin
We were collecting information on computer platforms that people would like ARP/wARP to run on. 126 people responded with 296 platform choices. The latter grouped as follows: Linux i686 26% Linux x86_64 24% Linux ia644% total Linux54% Mac powerpc 9% Mac Intel

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread James Holton
I made a movie demonstrating the effect of leaving out low-res data on an electron density map once: http://bl831.als.lbl.gov/~jamesh/movies/index.html#lores But it is interesting I think that the brightest reflections are actually what is important. Yes, the average spot intensity increases

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread Richard Gillilan
On Feb 20, 2009, at 2:58 PM, James Holton wrote: I made a movie demonstrating the effect of leaving out low-res data on an electron density map once: http://bl831.als.lbl.gov/~jamesh/movies/index.html#lores Very cool movie. Many thanks to those who answered my original question by private

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread Pavel Afonine
Sent on behalf of Sacha Urzhumtsev: Dear Richard, I answer to the whole CCP4bb since the question was quite general and the answer may be interesting for other people. As already mentioned by Bruno Klaholz, low-resolution reflections are not only a few reflections more but they contain

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread George M. Sheldrick
I agree with Pavel and would add that we have frequently found that collecting low resolution data on a home source and then merging it with the higher resolution synchrotron data collected subsequently from the same crystal can work wonders. The home source data tend to be missing fewer

Re: [ccp4bb] Importance of low order reflections?

2009-02-20 Thread Van Den Berg, Bert
Regarding the merging of regular datasets and low-res ones, what is the proper thing to do? Merging both complete datasets no matter what or cutting out the low-res data of the regular dataset? I.e. if the low-res data is not correctly measured in one dataset, would merging all data not be

[ccp4bb] Could I improve an inconsecutive experimental map?

2009-02-20 Thread Fengyun Ni
Hi everyone! I have a question on my poor MIR map. Four datasets (two AU and two HG) were used for phasing upto 3 A resolution in my case. I could locate several heavy atom sites for each dataset with occupancy finally refined to about 0.3 to 0.4, and with B value refined to about 50 to 80. I did