Jacob
Good question.
One case I know is for a metalloprotein where the photoreduction of the metal centre is decreased significantly at 40K compared with 110K.
Acta Cryst.<http://journals.iucr.org/d> (2007). D63<http://journals.iucr.org/d/contents/backissues.html>, 951-960
http://scripts.iucr.org/cgi-bin/paper?S0907444907035160
The paper offers a plausible explanation of why this effect occurs. The evidence is from x-ray spectroscopy rather than x-ray diffraction. Will the "subtle yet important changes" be seen with x-ray diffraction? Your plea for low temperature capability in conjunction with spectroscopic analysis is therefore relevant.
I too would be interested in any updates on this.
Regards
Colin
From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Keller, Jacob
Sent: 04 April 2017 00:06
To: ccp4bb
Subject: [ccp4bb] Helium-Temp Cryo-Cooling
Dear Crystallographers,
It is my recollection from a while ago that cryocooling to Helium temperatures has modest if any effects on protein structure or diffraction data quality, and I've found a couple of papers just now to that effect. Does anyone know differently? Do the b-factors even change?
Further, is anyone aware of a beamline which has really low temperature capability, ideally in conjunction with spectroscopic analysis?
All the best,
Jacob Keller
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Jacob Pearson Keller, PhD
Research Scientist
HHMI Janelia Research Campus / Looger lab
Phone: (571)209-4000 x3159
Email: [log in to unmask]<mailto:[log in to unmask]>
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