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
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________________________________
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] <mailto:[log in to unmask]>
