The short answer is: no. Wavelength does not matter. Not for native
data anyway.
I wrote a paper about this recently. It is open access:
http://dx.doi.org/10.1107/S0907444910007262
In particular, check out Figure 2. The two solid lines are pretty darn
flat, and that means the wavelength
the square of the wavelength.
Regards
Colin
-Original Message-
From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Bart Hazes
Sent: 16 February 2012 15:01
To: ccp4bb
Subject: Re: [ccp4bb] choice of wavelength
Hi Andrew,
I completely agree and it is what I meant
Dear Colleagues,
I think the following paper will be of particular interest for some
aspects of this thread:-
J. Appl. Cryst. (1984). 17, 118-119[ doi:10.1107/S0021889884011092 ]
Optimum X-ray wavelength for protein crystallography
U. W. Arndt
Abstract: If the diffraction pattern from
On 15 Feb 2012, at 23:55, Bart Hazes wrote:
Diffracted intensity goes up by the cube of the wavelength, but so
does absorption and I don't know exactly about radiation damage. One
interesting point is that on image plate and CCD detectors the
signal is also proportional to photon energy,
All,
I am curious to hear what our CCP4 community thoughts are
I have a marginally diffracting protein crystal (3-3.5 Angstrom resolution)
and would like to squeeze in a few tenth of angstrom.
Given that I am working on crystal quality improvement, would different
wavelengths make any
No impact ? Longer wavelength more absorption more damage. But between the
choices given no problem.
Spread of spots might be better with 1.0 versus 0.9 but that depends on your
cell and also how big your detector is. Given your current resolution none of
the mentioned issues are deal breakers.
Well, but there is more scattering with lower energy as well. The
salient parameter should probably be scattering per damage. I remember
reading some systematic studies a while back in which wavelength
choice ended up being insignificant, but perhaps there is more info
now, or perhaps I am
Acta Cryst. (1997). D53, 734-737[ doi:10.1107/S0907444997007233 ]
The Ultimate Wavelength for Protein Crystallography?
I. Polikarpov, A. Teplyakov and G. Oliva
http://scripts.iucr.org/cgi-bin/paper?gr0657
may give some insights.
To the OP, have you solved the structure? In some cases,
Diffracted intensity goes up by the cube of the wavelength, but so does
absorption and I don't know exactly about radiation damage. One
interesting point is that on image plate and CCD detectors the signal is
also proportional to photon energy, so doubling the wavelength gives 8
times
Hi all.
When collecting data, is there a specific wavelength to be chosen at
synchrotron source? Does it make difference between 0.9 and 1.5 A, for example?
I know it is important for SAD/MAD but how about MIR?
Thank you.
Theresa
If you are not looking for a specific metal, you can play it safe and
collect a redundant native data set at 0.9 A and one at 1.5 A, to check
for Ca,Cl,SO4 etc and other anomalous scatterers
cheers
Preben
On 2/13/12 10:02 PM, Theresa H. Hsu wrote:
Hi all.
When collecting data, is there a
On Mon, 2012-02-13 at 21:02 +, Theresa H. Hsu wrote:
Hi all.
When collecting data, is there a specific wavelength to be chosen at
synchrotron source? Does it make difference between 0.9 and 1.5 A, for
example? I know it is important for SAD/MAD but how about MIR?
Thank you.
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Choice of wavelength
Hi all.
When collecting data, is there a specific wavelength to be chosen at
synchrotron source? Does it make difference between 0.9 and 1.5 A, for example?
I know it is important for SAD/MAD but how about MIR?
Thank you.
Theresa
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