Generally speaking, don't we agree that "planned" or "rational" is
better than "random?" (Having trouble understanding the argument for
randomness here...)
Jacob
On Fri, Nov 18, 2011 at 9:40 AM, Sanishvili, Ruslan <[log in to unmask]> wrote:
> Depending on the crystal shape, “random orientation” is not always random.
> Many crystals have tendencies of sitting themselves in one predominant
> posture in the mount. Compounding this, many experimenters have tendencies
> of rotating the mount into a specific orientation when centering. Then
> crystal orientation ends up being not random at all, so understanding it’s
> true orientation as my neighbor Frank suggests can be highly beneficial.
>
> Cheers,
>
> N.
>
>
>
> Ruslan Sanishvili (Nukri), Ph.D.
>
> GM/CA-CAT
> Biosciences Division, ANL
> 9700 S. Cass Ave.
> Argonne, IL 60439
>
> Tel: (630)252-0665
> Fax: (630)252-0667
> [log in to unmask]
>
> ________________________________
>
> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Frank
> von Delft
> Sent: Friday, November 18, 2011 2:27 AM
> To: [log in to unmask]
> Subject: Re: [ccp4bb] crystal orientation during data collection
>
>
>
> I believe you achieve completeness more quickly (fewer crystals) if you just
> take random orientations. At least, that's what I learnt from Dave Stuart.
> phx
>
>
>
> On 18/11/2011 04:20, Frank Murphy wrote:
>
> Yanwu,
>
>
>
> I surmise from your question that you are inquiring how to go about
> collecting from many crystals optimally. Merging data ex post facto is a
> totally different kettle of fish.
>
>
>
> In my opinion, the most robust way to go about this is to use a kappa
> goniometer as Jim suggested (I am most familiar with the MK3). Since you
> intend to collect from many crystals, align the first and all subsequent
> crystals to the same easily attainable (or seemingly so) orientation, and
> then collect the sweep suggested by your data collection strategy program of
> choice.
>
>
>
> To achieve this at NE-CAT, we have a GUI-based system that used STAC for
> orientation determination and BEST for strategy generation. As Jim
> suggested, more options than STAC exist.
>
>
>
> If anyone is unable to get to a kappa goniometer, they can employ Mosflm or
> XDS (Xplan) to generate strategies for data collection from a crystal taking
> into account previously collected data. This is not nearly as robust a
> solution, but is a workable substitute (and also automated at NE-CAT).
>
>
>
> I know there are other ways to achieve similar results, but I have suggested
> the methods I am most familiar with...
>
>
>
>
>
> Yours,
>
> Frank Murphy
>
>
>
>
>
> Begin forwarded message:
>
> From:
>
> yanwu huo <[log in to unmask]>
>
> Date:
>
> November 17, 2011 4:00:06 PM CST
>
> To:
>
> [log in to unmask]
>
> Subject: [ccp4bb] crystal orientation during data collection
>
> Reply-To:
>
> yanwu huo <[log in to unmask]>
>
> Hi,
> I worked on a crystal sensitive to radiation damage, So I need to merge many
> crystal to obtain complete dataset, Does anyone know such program that can
> tell crystal orientation after first frame exposure.
> Thank you in advance.
>
>
> --
> Thank you very much and all the best,
>
> Yanwu Huo
> Postdoctoral Associate
> Department of Molecular Biology and Genetics
> Cornell University
> Ithaca, NY, 14853
> Email:[log in to unmask]
>
>
>
>
>
>
>
>
>
--
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
email: [log in to unmask]
*******************************************
|