Re: [ccp4bb] Helium-Temp Cryo-Cooling

2017-04-04 Thread Jan Kern 
Hi Jakob,

There are several other examples where the effect of temperature on
radiation damage for metallo proteins was demonstrated, eg:
10.1074/jbc.M112.438796
10.1073/pnas.0505207102
10.1074/jbc.M509724200

The tricky part with liq He cryo streams is to get a good geometry that
provides stable temperature and prevents severe icing. Usually, for
spectroscopic experiments we used to mount our sample from the bottom with
the pin pointing vertically up (instead of mounting it with the pin
horizontally) in order to prevent disturbing of the He flow and reduce
icing. But of course this geometry is difficult to achieve in most standard
MX beam lines. I thought there was some initiative maybe 8-10 years ago at
APS and at ESRF to get a He cryo jet running at one of their MX beam lines
but I do not remember the details.

Greetings,

Jan

On Tue, Apr 4, 2017 at 2:14 AM, Colin Nave <colin.n...@diamond.ac.uk> wrote:

> 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:CCP4BB@JISCMAIL.AC.UK] 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
>
>
>
> ***
> Jacob Pearson Keller, PhD
> Research Scientist
> HHMI Janelia Research Campus / Looger lab
> Phone: (571)209-4000 x3159
> Email: kell...@janelia.hhmi.org<mailto:kell...@janelia.hhmi.org>
> ***
>
>
> --
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>

Re: [ccp4bb] Helium-Temp Cryo-Cooling

2017-04-04 Thread Colin Nave 
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:CCP4BB@JISCMAIL.AC.UK] 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



***
Jacob Pearson Keller, PhD
Research Scientist
HHMI Janelia Research Campus / Looger lab
Phone: (571)209-4000 x3159
Email: kell...@janelia.hhmi.org<mailto:kell...@janelia.hhmi.org>
***


-- 
This e-mail and any attachments may contain confidential, copyright and or 
privileged material, and are for the use of the intended addressee only. If you 
are not the intended addressee or an authorised recipient of the addressee 
please notify us of receipt by returning the e-mail and do not use, copy, 
retain, distribute or disclose the information in or attached to the e-mail.
Any opinions expressed within this e-mail are those of the individual and not 
necessarily of Diamond Light Source Ltd. 
Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments 
are free from viruses and we cannot accept liability for any damage which you 
may sustain as a result of software viruses which may be transmitted in or with 
the message.
Diamond Light Source Limited (company no. 4375679). Registered in England and 
Wales with its registered office at Diamond House, Harwell Science and 
Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom

[ccp4bb] Helium-Temp Cryo-Cooling

2017-04-03 Thread Keller, Jacob 
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



***
Jacob Pearson Keller, PhD
Research Scientist
HHMI Janelia Research Campus / Looger lab
Phone: (571)209-4000 x3159
Email: kell...@janelia.hhmi.org
***