Re: [ccp4bb] Confused about centric reflections

2019-03-02 Thread Dale Tronrud
You are correct, other than your typo. The centric zone in a monoclinic space group (B setting) is h0l. This web site is a wiki so you should be able to correct it yourself. Dale Tronrud On 3/2/2019 2:00 PM, Edward A. Berry wrote: > The wiki: > >

Re: [ccp4bb] (EXTERNAL) RE: [ccp4bb] Confused about centric reflections

2019-03-02 Thread Edward A. Berry
On 03/02/2019 09:59 PM, Ronald E. Stenkamp wrote: I was taught about centric reflections using different words from those in the wiki. If you look at your crystal structure in projection and the planar view looks centrosymmetric, the zone of reflections corresponding to that projection will

[ccp4bb] Confused about centric reflections

2019-03-02 Thread Edward A. Berry
The wiki: https://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Centric_and_acentric_reflections says: "A reflection is centric if there is a reciprocal space symmetry operator which maps it onto itself (or rather its Friedel mate). . . . Centric reflections in space group P2 and P21 are

[ccp4bb] KCl in SDS-PAGE workarounds?

2019-03-02 Thread Keller, Jacob
Dear crystallographers, It has been my experience that KCl does nasty things when loading SDS-PAGE gels. Does anyone have an easy workaround, perhaps TCA precipitation? Ideally this would be something nicely quantitative yet quick and easy…. Any suggestions appreciated. All the best, Jacob

Re: [ccp4bb] ionic strength for extraction buffer of membrane proteins

2019-03-02 Thread Artem Evdokimov
Hi Alex, In my experience you just have to experiment with these parameters (in however of a limited space that is afforded by your experimental set-up). If you have the right tools you can slog through semifactorial or DoE-based scouting of various parameters with relative ease. These parameters

Re: [ccp4bb] KCl in SDS-PAGE workarounds?

2019-03-02 Thread Bonsor, Daniel
SDS is soluble, whereas the potassium salt of dodecyl sulphate is insoluble. You could try 18-Crown-6 ether to chelate the potassium, though I don't know if the crown ether would then affect the gel. Dan Daniel A. Bonsor PhD Institute of Human Virology, University of Maryland at Baltimore

Re: [ccp4bb] Confused about centric reflections

2019-03-02 Thread Edward A. Berry
Thaks! typo- h,0,l not h,0,k I have not registered for editing on that wiki, so I was hoping someone else would take care of it. But it seems all that's needed is to confirm your account, so I'll register and give it a try. Hope I don't make things worse! (what is this urldefense.proofpoint? did