[Myotox] SDS AUC update

[Henrickson, Amy]

Hello,

Just to clarify the SDS concentration was 1%(w/v).

Cheers,
Amy Henrickson
________________________________
From: Myotox <myotox-bounces at biophysics.uleth.ca> on behalf of Borries Demeler <demeler at gmail.com>
Sent: Thursday, March 12, 2020 2:45 PM
To: myotox at biophysics.uleth.ca <myotox at biophysics.uleth.ca>
Subject: [Myotox] SDS AUC update

Dear all,
Amy ran the most recent samples from Bruno in the presence of 1 mg/ml
SDS at two protein concentrations (1 mg/ml and 0.17 mg/ml). The results
are quite consistent with the results in Susumu's paper. We do see
oligomerization, with a more or less final state. At this point I am not
clear if it is a dimer or trimer or something higher, this still needs
to be determined. But it is very clear that SDS has a big effect on
dimerization. What also is interesting is that the association behavior
induced by SDS appears to be reversible. That is, you get dissociation
of the oligomer in response to lowering the concentration. We will
further test this by using even lower concentration to see if we can
shift to entirely monomer. We will also do D2O density matching to see
if there is a density difference between monomer and dimer and
potentially higher oligomers due to different ratios of SDS binding to
myotoxin-II.

Now we need to come up with a strutural explanation why this
oligomerization shift is happening in response to addition of SDS. I
would also like to know if some other lipids could cause the same effect
as a detergent? A figure is attached that shows the sedimentation
distribution, it looks like similar values as those obtained for the
different toxin in the Uchiyama paper.

Regards, -Borries


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