[Demelerlab] AUC Collaboration: Sizing Amyloid Beta derived Oligomers

[Borries Demeler]

I forgot to mention that the drop at the lowest wavelength is probably
related to very little light from the light source, making the device
nonlinear at nearly all wavelengths. Yes, the peptide bond absorbs there,
but the lower you go in wavelength, the less light intensity you will have
and the device just becomes non-linear. No amount of baseline scanning will
take care of nonlinear signals.

-Borries

On Tue, Jul 18, 2023 at 1:59 PM Jason Zhu <jasonz13 at uci.edu> wrote:

> Hi Borries,
>
> Apologies for the belated response, the purifications took a bit longer
> than expected.
>
> I tried adding Tris (at pH 6.0 and pH 9.0) to 1 mM F19Cha and observed
> salting out at 10-50 mM Tris so it is not a viable additive to prevent
> non-ideal effects unfortunately.
>
> I ran nanopure water (blank), nanopure water with 0.1 % TFA (ca. 10 mM)
> and 1 mM F19Cha dissolved in nanopure water on our nanodrop. I see a slight
> negative peak when 0.1% TFA is added (run 1) and that this peptide absorbs
> strongly even at 1 mM F19Cha (run 2) on our nanodrop.
> [image: image.png]
> I have some purified F19Cha (~24 mgs) that is ready for shipping. I can
> weigh out the peptides and write out the corresponding volumes of solution
> to add for our AUC studies. What would be the best address to ship to and
> when should I ship these peptides?
>
> Best regards,
> Jason
>
> On Sun, Jul 9, 2023 at 1:23 PM Borries Demeler <demeler at gmail.com> wrote:
>
>> Hi Jason,
>> thanks for the PDB files, as I suspected we need new definitions for the
>> various non-canonical AAs. I get errors when running SOMO on the undefined
>> residues. I asked Emre from our group to suggest a way how to deal with
>> this. Presumably someone needs to edit the definitions for the unknown
>> residues. I'll give you some updates when I have them.
>>
>> Regards, -borries
>>
>> On Thu, Jul 6, 2023 at 11:37 PM Jason Zhu <jasonz13 at uci.edu> wrote:
>>
>>> Dear Borries and the Demeler lab,
>>>
>>> As a follow-up to our conversation today, I've attached my slides, PyMOL
>>> models for the crystallographic F19Cha hexamer and the proposed NMR
>>> dodecamer based on a structural analog (PDB ID: 5v63). I broke up the
>>> subunits of the crystallographic hexamer and proposed NMR dodecamer into
>>> separate pdb files to make them easier to work with.
>>>
>>> In the meantime, I'll try adding Tris to my peptide, running samples on
>>> the nanodrop, purifying more F19Cha and will keep you posted.
>>>
>>> Thanks again for setting up this meeting and having so many members of
>>> your lab attend. Please feel free to reach out if there's anything you need
>>> from our end. I look forward to working with you all! :)
>>>
>>> Kind regards,
>>> Jason
>>>
>>
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