Hi Ibrahim,
On 04/06/07, Ibrahim M. Moustafa <[EMAIL PROTECTED]> wrote:
Hi all,
While reading a crystallographic paper describing the structure
of an apo-protein and its complex I noticed that
the authors described the space goup as P6122 for the unit cell:
a=141.9, b=143.9, c=380.4
Could this be considered as a typo or I'm missing something here!
the requirement for the hexagonal is a = b # C....right?
You are correct, for Hexagonal, a=b - so It's got to be a typo - data most
processing software wouldn't let you do this.
Another observation in that paper too: the B-factors for the 2.4 A
and 3.2 A structures are 39 and 40?? Does this make sense to anyone?
They're quoting Wilson B-factors, I imagine. A small but rather important
difference - where was this published?
The last question: In the same paper, for the complex structure R and
Rfree are equal (30%) is that an indication for improper refinement
in these published structure? I'd love to hear your comments on that too.
Well, it certainly is a little suspicious looking - I've had similar
experiences to Ed, regarding similar R & Rfrees from rigid rigid body
refinement prior to positional refinement. Have the authors deposited the
Structure factors? I would use EDS to check the maps out: eds.bmc.uu.se/eds/
thanks,
Ibrahim
HTH, Dave
--
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David Briggs, PhD.
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www.dbriggs.talktalk.net
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