EOM poor fit at high q

Linear (OLIGOMER), and non-linear (MIXTURE) analysis, singular value decomposition (SVDPLOT), addition of missing fragments (BUNCH, CORAL), analysis of flexible systems (EOM/RANCH & GAJOE), flexible refinement of high-resolution models (SREFLEX)
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FrankG
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Posts: 9
Joined: 2017.05.17 11:02
Location: Lyon

EOM poor fit at high q

#1 Post by FrankG » 2019.02.28 11:28

Hi everyone,

I'm annoyed with the EOM output:
the fit systematically differs from the experimental data at high q.
I've firstly used IDP dihedral angles and the fit diverged at around 0.4 1/A
With random coil dihedral angles, the fit is better but diverged according to CorMap at around 0.45 1/A.

It seems the intensity decreases lower than 1/q2, which is the "limit" for pure random-coil if I'm not mistaken.
Changing the number of harmonics, points or pool size did not improve the fit.

Additionally, I've checked the buffer subtraction by comparing the buffer curves with CorMap (It was a SEC-SAXS experiment) and the smax was estimated with Shanum.

Do you have any advice ? I'm very lost ! :(

Thank you very much,

Frank

PS: I ran EOM online and on my PC too and the protein sequence and integrity have been verified by MS

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