[3dem] Resolution Criteria in 3D data processing (cryo-EM)
Marin van Heel
marin.vanheel at googlemail.com
Fri Nov 24 14:46:27 PST 2017
Dear All,
Impressive as the cryo-EM results of the resolution resolution may be, a
fundamental statistical error has persisted in the literature that
affects almost all cryo-EM quality metrics (FSC-0.143, FSC 0.5; DPR 45,
SSNR, Gold Stardust FSC, etc ...) One of the very few survivors of this
methodology onslaught is the FSC 1/2 bit criterion. The numerical
resolution values for practically all published structures have no
absolute meaning and can therefore not be compared to each other. The
error goes back to a misinterpretation of basic statistics made in the
1970s and pervaded virtually all popular cryo-EM quality metrics. It
may frustrate many of you to have to change your way of thinking or the
programs you are using, but that is what science requires you to do now.
Alternatively - following strict scientific standards - you can try
prove us wrong with real scientific arguments (carefully read our paper
before you start criticizing). Even if 99% of cryo-EM practitioners use
incorrect metrics, that does not make the metrics right! Science is not
a democracy ... We are of course aware that with this paper we are
refuting a huge number of methodological papers all at once, with many
people involved who will undoubtedly be left frustrated. If that is of
any help, I also feel frustrated that it took me (us) far too long to
get to the core of the matter so as to resolve these issues once and for
all. On the positive side, we can now all be relieved of the eternal and
repetitive FSC jokes at cryo-EM meetings!
For now, good night and have a good weekend!
Marin
our BiorXiv contribution ca be found here:
https://www.biorxiv.org/content/early/2017/11/24/224402
--
==============================================================
Prof Dr Ir Marin van Heel
Laboratório Nacional de Nanotecnologia - LNNano
CNPEM/LNNano, Campinas, Brazil
tel: +55-19-3518-2316
mobile +55-19-981809332
(041-19-981809332 TIM)
Skype: Marin.van.Heel
email: marin.vanheel(A_T)gmail.com
marin.vanheel(A_T)lnnano.cnpem.br
and: mvh.office(A_T)gmail.com
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Emeritus Professor of Cryo-EM Data Processing
Leiden University
Mobile NL: +31(0)652736618
Emeritus Professor of Structural Biology
Imperial College London
Faculty of Natural Sciences
email: m.vanheel(A_T)imperial.ac.uk
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