Re: [ccp4bb] salt sensitive complex

2008-01-23 Thread David Briggs
Hi Jerry, to summarise your problem, using (close to) physiological buffer, SPR and ITC give you different results, you get different results in different salt strengths and to add to your misery, the proteins precipitate at low salt concentrations when mixed to together. Ok. Given the above,

Re: [ccp4bb] Characterization of common salt crystal forms?

2008-01-23 Thread David Briggs
Hi Joe, I've known most salt crystals in Phosphate - and I think most people are weary of phosphate. Also, Calcium Sulphate is a fairly common one, esp if your buffers are titrated with sulphuric acid. Fluoride Ions are also prone to form salt crystals with transition metal ions. HTH, Dave

Re: [ccp4bb] microsoft 3-button wheel mouse with OS X 10.5

2008-01-23 Thread mb1pja
Dear Bill William Scott wrote Aqua simply behaves by slightly different rules. Although I am a slobbering OS X fan, this lack of customizability to me, as well as a lack of focus-follows-mouse, it a negative. To get focus-follows-mouse in Aqua, type the following in your Terminal

Re: [ccp4bb] Why there are difference density when occupancy is 1.00

2008-01-23 Thread Eleanor Dodson
Hard to say without more information. Have you refined the B factors for these residues? Most building software gives some arbitrary b value, which must then be refined. (In fact after any rebuilding activity you need to do a few cycles of refinement before looking at the maps again)

[ccp4bb] Question about freeR tag

2008-01-23 Thread Zheng Zhou
Hi, All Could any tell me how CCP4 handle free R flag? I know It is important to select the same** FreeR reflections if I move to next step of refinement. But everytime I start from fresh, the freeR Flag remains unchanged. The Rwork and Rfree of my models are fine (20.7% and 22.9%). I thought

Re: [ccp4bb] microsoft 3-button wheel mouse with OS X 10.5

2008-01-23 Thread William Scott
Yes, thanks, that does it for the Terminal.app, but not for any of the rest. It would be great to have such a feature globally. mb1pja wrote: Dear Bill William Scott wrote Aqua simply behaves by slightly different rules. Although I am a slobbering OS X fan, this lack of customizability to

[ccp4bb] problem on protein precipitation

2008-01-23 Thread Zheng, Lei
Hi ccp4ers, Sorry for this out-topic question: Recently we have a membrane protein expressed, after solubilized with detergent and purified from IMAC, the protein looks beautiful in SEC. However, it completely precipitates after the 2-3 days storage in 4 degree. We supplement 2 mM DTT in the

Re: [ccp4bb] Question about freeR tag

2008-01-23 Thread Zheng Zhou
Sorry that I didn't explain the situation clearly. I used only one output.sca file from HLK2000. I ran the scalepack2mtz (in CCP4i, data reduction, import merged data) several times, on both linux Fedora and window XP, the same computer though. For the next step refinement, I mean add H2O, ion,

Re: [ccp4bb] problem on protein precipitation

2008-01-23 Thread Lisa A Nagy
Hi Lei, Try this: 50-100 mM Arginine in your buffers. Or Glutamic Acid. Or both. -- Lisa A. Nagy, Ph.D. University of Alabama-Birmingham [EMAIL PROTECTED] From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of Zheng, Lei Sent: Wednesday, January 23, 2008 10:51 AM

Re: [ccp4bb] Question about freeR tag

2008-01-23 Thread Roger Rowlett
Zheng Zhou wrote: Hi, All Could any tell me how CCP4 handle free R flag? I know It is important to select the same** FreeR reflections if I move to next step of refinement. But everytime I start from fresh, the freeR Flag remains unchanged. The Rwork and Rfree of my models are fine ( 20.7%

Re: [ccp4bb] Why there are difference density when occupancy is 1.00

2008-01-23 Thread Sun Tang
Hi James, I did check teh B-factors and they are similar to the flanking regions (about 40). The difference density appeared at the later stage of refinement (TLS and restrained in CCP4i). What do you think and how to do it? Best, Sun Tang James Irving [EMAIL PROTECTED] wrote: Hi Sun, I

Re: [ccp4bb] Question about freeR tag

2008-01-23 Thread Edwin Pozharski
FREEFLAG (the program which is used to generate the test set) description says when describing the keyword SEED: By default, for a given job on a given machine, the random number generator produces the same list of random free-R flags each time the job is run. Since you would generally only

Re: [ccp4bb] Question about freeR tag

2008-01-23 Thread Zheng Zhou
Thank you all for fast replying. The reason that I am trying to use a different set of FreeR flag from the very beginning of the refinement is that for some data set, my colleague's CNS refinement gave converged Rfree and R work, 3% difference. However both my CNS and CCP4 refinement gave a

[ccp4bb] meeting suggestions

2008-01-23 Thread Ingrid . Mechin
Dear All, I have a probably quite controversial question for the crystallographic community (and there may be a strong personal bias too...). Our group would like to select 4 meetings this year that would really be focused towards our line of work (protein crystallography in collaboration

[ccp4bb] GPCR Structural Biology Postdoctoral Position Openings

2008-01-23 Thread Ray Stevens
GPCR Structural Biology Postdoctoral Position Openings We have several openings for postdoctoral fellows in the area of GPCR structural biology in the Kuhn-Stevens Laboratory at The Scripps Research Institute. With the recent structure determination of the human beta2 adrenergic receptor