From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Dean
Derbyshire
Sent: 30. april 2014 12:33
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] metals disapear
Hi all,
Has anyone experienced catalytic metal ions disappearing during data collection
?
If so, is there a way
From: zbys...@work.swmed.edu [zbys...@work.swmed.edu]
Sent: Wednesday, April 30, 2014 10:33 AM
To: Sanishvili, Ruslan
Cc: ccp4bb@jiscmail.ac.uk
Subject: Re: [ccp4bb] metals disapear
If metal ion will be sensitive to radiation depends on its redox chemistry
and not its X-ray
Dear All,
So there has been quite a bit of advice on minimising radiation
damage, and on some of the effects of radiation damage, but unless I have
missed it no-one has come up with a clear cut case where radiation damage
actually resulted in the (complete ?) loss of a metal
10:33 AM
To: Sanishvili, Ruslan
Cc: ccp4bb@jiscmail.ac.uk
Subject: Re: [ccp4bb] metals disapear
If metal ion will be sensitive to radiation depends on its redox chemistry
and not its X-ray properties. For a metal to be affected by radiation dose
it needs to be reduced by free radicals
Dear Dean,
I appreciate you might not be able to reveal further details but 'disappearing
during data collection' sounds interesting as does 'metals' plural (are
they expected to be close together?).
Best wishes,
John
Prof John R Helliwell DSc
On 30 Apr 2014, at 11:33, Dean Derbyshire
Hi all,
Has anyone experienced catalytic metal ions disappearing during data collection
?
If so, is there a way of preventing it?
D.
Dean Derbyshire
Senior Research Scientist
[cid:image001.jpg@01CF6470.5FA976D0]
Box 1086
SE-141 22 Huddinge
SWEDEN
Visit: Lunastigen 7
Direct:
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Hash: SHA1
Dear Dean,
this is probably a very common observation: X-rays produce reducing
electrons and as you reduce a metal I imagine it does not like its
chemical environment as much as it did highly charged.
Everything you can do to avoid radiation damage
Can the radiation damage gurus comment on this ? I know there is a problem with
radiation damage changing the valence state of metals, but I don't remember
hearing about the metal actually being lost due to radiation damage. Is this
really common ?
Thanks,
Andrew
On 30 Apr 2014, at 11:46,
30, 2014 6:33 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] metals disapear
Hi all,
Has anyone experienced catalytic metal ions disappearing during data collection
?
If so, is there a way of preventing it?
D.
Dean Derbyshire
Senior Research Scientist
[cid:image001.jpg@01CF6450.2D6A0D80
Dear Dean (and Andrew),
I am certainly no radiation damage guru, but at the RD8 Workshop in
Hamburg 3 weeks ago (http://www.rd-eight.org/RD8-01/) I heard a talk by
Pernille Harris about the photoreduction by X-rays of Cu(II) to Cu(I) in a
Cu-insulin crystal.
Tim's description couldn't
My comments:
Such observation is very uncommon for metals involved in catalysis by
proteins. I have seen quite a few such structures involving Mg, Ca, Fe,
Mn, Zn and most of the radiation damage was not at the catalytic metal. In
case of Fe once I noticed slight shift in the position of the Fe
Dear Dean
An example, albeit not a metal, can be found here:-
http://journals.iucr.org/s/issues/2007/01/00/xh5011/xh5011.pdf
Such specific damage has a long history:-
http://www.sciencedirect.com/science/article/pii/0022024888903223
An X-ray sensitive metals centre is the Mn5Ca OEC of PS II and
:33 AM
To: Sanishvili, Ruslan
Cc: ccp4bb@jiscmail.ac.uk
Subject: Re: [ccp4bb] metals disapear
If metal ion will be sensitive to radiation depends on its redox chemistry
and not its X-ray properties. For a metal to be affected by radiation dose
it needs to be reduced by free radicals. However
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