[ccp4bb] Hg rippled summary

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CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Tweaking with SCBUlk and BBULk parameters in refmac
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-08-06

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Subject: Re: Calculating vertical offset of helices
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-08-06

Subject: Hg rippled summary
From: Klemens Wild Klemens {- dot -} Wild {- at -} BZH {- dot -} UNI-HEIDELBERG {- dot -} DE
Date: 2007-08-06

Dear colleagues,

here some comments about our Hg ripple problem - many thanks to all your
answers:

Indeed we were not able to completely get rid of the ripples (as stated
by Bart Hazes: not really affecting the biological conclusions - but
anyway!). Summarizing the suggested problems are: summation truncation,
anomalous scattering, anisotropy, multiple conformations, radiation
damage, occupancy.
We already did the occupancy refinement beforehand, which helped as well
as the anisotropic B refinement. Changing resolution limits did not help
much - anyhow unfortunately we do not have higher resolution collected
and data stops at the overall I/sigI at 3 sigma. Changing from Hg to
Hg+1 (compound originally was ClHgCH3) helped in decreasing R-factors,
although I always thought there should be covalent binding to Cys.
Changing f' did not seem to have a big impact, although it is clearly
different (approx. -11) from the standard CCP4 library for CuKa (-5.0)?!
BTW: the Hg peaks are only 25 sigmas, and not 80 and dual conformations
were not obvious.

Thanks to: ClemensV, KayD, GeorgeS, BartH, DavidS, KevinJ, EleanorD,
TassosP, TommiK, PeterM

Klemens Wild

CCP4bb navigation

CCP4bb <-- 1999 <-- November 1999 <-- 30 November 1999

Previous message:
Subject: Re: Tweaking with SCBUlk and BBULk parameters in refmac
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-08-06

Next message:
Subject: Re: Calculating vertical offset of helices
From: Eleanor Dodson ccp4 {- at -} YSBL {- dot -} YORK {- dot -} AC {- dot -} UK
Date: 2007-08-06