this cant be true,
in the idea case (not Rmerge 15%, then again one can apply a resolution
cutoff, perhaps, while this sounds like a very desperate case) the
answer must be yes. didnt do the calculation right now (but it
_should_ back this up)
we for instance have solved a structure long time ago
-- and this probably wasnt on the limit (well it was at the time but
not anymore), 365 res x 8 in AU and 80 Se.
at least looking at the SnB success list ("very" old list )
http://www.hwi.buffalo.edu/SnB/SnBSuccesses.htm
there are plenty of others.
-tommi
On Mar 20, 2009, at 10:53 PM, Bernhard Rupp wrote:
> One can estimate this from
>
> http://www.ruppweb.org/new_comp/anomalous_scattering.htm
>
> and the answer as Jim says is no.
>
> BR
> -----Original Message-----
> From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf
> Of Jim
> Pflugrath
> Sent: Friday, March 20, 2009 1:08 PM
> To: [log in to unmask]
> Subject: Re: [ccp4bb] Problems with phasing a protein (1300aa)
>
> Well, what do you expect the anomalous signal contributed from your 45
> seleniums in a perfect world to be when the asymmetric unit contains
> 1300
> aa? Do you think a dataset with Rmerge of ~15% is good enough to
> detect a
> signal of even 2%? (Note: I did not do the calculation, so I just
> made up
> the number of 2%.)
>
> Jim
>
>
> On Fri, 20 Mar 2009, Kumar wrote:
>
>> Hello CCP4bb members,
>>
>> I have been trying to obtain phases for a protein which contain
>> ~1300aa.
> We
>> have obtained native data to a resolution of 3.3A (Space group I222
>> or
>> I212121). But we are having tough time phasing it.
>> ...
>
Tommi Kajander, Ph.D.
Structural Biology and Biophysics
Institute of Biotechnology
University of Helsinki
Viikinkaari 1
(P.O. Box 65)
00014 Helsinki
Finland
p. +358-9-19158903
[log in to unmask]
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