[Myotox] Myotoxin discussion

Tue Nov 26 11:08:51 MST 2019

Hi all and thank you for adding me to the mailing list.

 Julián

On Tue, Nov 26, 2019 at 9:49 AM Borries Demeler <demeler at gmail.com> wrote:

>
> Thanks Harmen for the detailed explanation on the membranes. Paul/Tony,
> would
> you suggest we try liposomes first, or try some other membrane system.
>
> Harmen: Do you know how to prepare liposomes of homogenous size? We
> could verify size homogeneity of liposomes on the AUC.
>
> Julian: With your permission, I will add you to our mailing list, OK?
>
> -Borries
>
>
> On Mon, Nov 25, 2019 at 11:28:21PM -0600, Bruno Lomonte wrote:
> > Thank you Harmen and greetings to all,
> >
> > just a short note to let you know that regarding *liposomes *there is a
> > group in Mexico already exploring permeabilization (calcein release)
> caused
> > by this myotoxin - they are mostly focusing on ergosterol-containing
> > liposomes (trying to approach fungal-like bilayers), but I though it is
> > important that we are all aware of it, just to avoid any potential
> overlaps
> >
> > I hope that this is OK with you, and that there may be different models
> > which do not overlap with those liposome permeabilization studies
> >
> > please allow me to copy this message also to my colleague Julian
> Fernandez,
> > with whom we work together in the characterization of myotoxins in Costa
> > Rica
> >
> > kind regards,
> >
> > Bruno
> >
> >
> > ++++
> >
> >
> >
> > On 25/11/2019 22:14, Steele, Harmen wrote:
> > > The SMA synthetic belts are highly negative.  In the electrostatic
> interactions with cytc we could never tell the difference between lipid and
> belt interactions.  To tell the differences in these interactions we had to
> us the biological belt, which are neutral in charge.  The SMA nanodiscs are
> uniform in size and shape when there is a membrane bound protein embedded.
> Without a membrane bound protein (pure lipid NDs), the nanodiscs are more
> homogeneous in size and shape.
> > >
> > > I have done some work using fluorescence anisotropy and various probes
> that embed in the lipid bilayers to examine the effect that various metal
> nanoparticles have on bilayer order.  The anisotropy gives us a way to
> study the degrees of freedom that a probe has in the lipid bilayer. These
> degrees of freedom can give us an idea of the order or disorder of a lipid
> bilayer.  By altering the lipid composition of a bilayer we could get an
> idea of what types of lipids are interacting with myotoxin resulting in
> leaky membranes.  I was thinking we start with a composition that resembles
> muscle and then alter the bilayer as we hone in on the specific lipid
> interactions.
> > >
> > > I don't think that nanodiscs would be the best model system to study
> this interaction. I believe that the belt protein provided a lateral
> pressure on the lipid bilayer that would inhibit and/or negate any changes
> a particle might have on the lipid bilayers packing order. I think that
> liposomes would be a more appropriate system.  Additionally, doing some
> studies with muscle cells would be appropriate too.
> > >
> > >
> > > Best regards,
> > > Harmen Steele, Ph.D.
> > > Postdoctoral Researcher
> > > harmen.steele at umontana.edu
> > > +406 529 9669 - mobile
> > > Skype Me: harmensteele <callto://harmensteele/>
> > > Amateur Radio Call Sign: K9HBS
> > > I am a UM Ally <http://www.umt.edu/umallies/>
> > > This email was sent using 95% recycled binary bits and 99.9% recycled
> electrons.
> > >
> > > On 11/22/19, 4:55 PM, "Myotox on behalf of Borries Demeler" <
> myotox-bounces at biophysics.uleth.ca on behalf of demeler at gmail.com> wrote:
> > >
> > >      Hello all,
> > >      I am forwarding the information from Bruno to the mailing list so
> we
> > >      have a record there, including the attached papers so you all have
> > >      access to them.
> > >      In addition: Tony/Mike and Paul: Amy has ~ 100 ul of pure
> myotoxin-II at
> > >      21 mg/ml (high concentration) available. It is in phosphate
> buffer as
> > >      far as I know. We could get that to you. If you need more, I am
> sure
> > >      Bruno could arrange another shipment.
> > >      I also discussed the project with Harmen. He had a lot of
> interesting
> > >      ideas with respect on how to prepare nanodisks and membranes, and
> how
> > >      to check the interaction with Mytoxin-II with the membrane. He
> has been
> > >      working on a very similar project testing destruction of
> mitochondrial
> > >      membranes by cytochrome-C, Paul, this is the project we wanted to
> pursue
> > >      with you. Harmen sent some samples to you guys earlier, not sure
> if they
> > >      were ever analyzed, but perhaps we could pick this up again as
> well?
> > >      (and Paul, feel free to add this into the discussion for the CFI,
> since
> > >      it would be another excellent example for the collaboration
> between our
> > >      groups and justify the CMP-MAS probe).
> > >      Harmen, I'm going to let you chime in and share your ideas on
> synthetic
> > >      belts, and various types of lipids that could be used for making
> > >      appropriate nanodiscs. Perhaps you could also find the source for
> the
> > >      muscle tissue membrane lipids you talked about, as well as some
> other
> > >      more readily available membrane systems we could try.
> > >      Bruno indicated that most membranes would be affected by the
> toxicity
> > >      to some degree (what's different about the membranes of the
> snake's
> > >      toxin-producing glands/toxin-conducting tissues??)
> > >      Thanks, -b.
> > >      ----- Forwarded message from Bruno Lomonte <
> bruno.lomonte at ucr.ac.cr> -----
> > >      Date: Fri, 22 Nov 2019 12:01:25 -0600
> > >      From: Bruno Lomonte <bruno.lomonte at ucr.ac.cr>
> > >      To: "Montina, Tony" <tony.montina at uleth.ca>, "Hazendonk, Paul" <
> paul.hazendonk at uleth.ca>, "Opyr, Michael"
> > >             <michael.opyr at uleth.ca>, Borries Demeler <
> demeler at gmail.com>
> > >      Subject: Re: Research Collab Meeting
> > >      User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0)
> Gecko/20100101 Thunderbird/60.9.1
> > >      Thanks so much to all for your interest in exploring
> possibilities to
> > >      study the interaction of the myotoxin II with membranes.
> > >      here attached is the paper in which some phospholipid compositions
> > >      were studied using liposomes, back in 1992
> > >      there was also a follow up with an interesting observation about
> > >      potential auto-acylation of the myotoxin (also attached, 1995)
> > >      codes for the crystal structe of the protein are:  1CLP and 1Y4L
> > >      some info about the active region of the toxins here attached too
> (2001)
> > >      happy to provide any further info, and of  course, protein, if you
> > >      find this project is viable and interesting
> > >      special thanks to Borries for bridging our interests
> > >      all the best,
> > >      Bruno
> > >
> > > _______________________________________________
> > > Myotox mailing list
> > > Myotox at biophysics.uleth.ca
> > > http://demeler7.uleth.ca/mailman/listinfo/myotox
> >
> > --
> > Bruno Lomonte, Ph.D.
> > Instituto Clodomiro Picado
> > Universidad de Costa Rica
> > San José, 11501
> > COSTA RICA
> >
> > bruno.lomonte at ucr.ac.cr
> > tel. +506  2511 7888
> > cel. +506  8392 0012
> >
>
> > _______________________________________________
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> > Myotox at biophysics.uleth.ca
> > http://demeler7.uleth.ca/mailman/listinfo/myotox
>
>
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