i was just refering to the mentioned "ideal case" with 43 se and 1300
aa in AU, and some real (successful) examples of same size range.
-tommi
Quoting "Bernhard Rupp" <b...@ruppweb.org>:
What is not true?
Also in your case the applet estimates an expected
4-5% signal which is quite doable with decent data.
BR
-----Original Message-----
From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Tommi
Kajander
Sent: Friday, March 20, 2009 3:43 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: Re: [ccp4bb] Problems with phasing a protein (1300aa)
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:ccp...@jiscmail.ac.uk] On Behalf
Of Jim
Pflugrath
Sent: Friday, March 20, 2009 1:08 PM
To: CCP4BB@JISCMAIL.AC.UK
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
tommi.kajan...@helsinki.fi
--
Tommi Kajander, Ph.D.
Macromolecular X-ray Crystallography
Research Program in Structural Biology and Biophysics
Institute of Biotechnology
P.O. Box 65 (Street address: Viikinkaari 1, 4th floor)
University of Helsinki
FIN-00014 Helsinki, Finland
Tel. +358-9-191 58903
Fax +358-9-191 59940
