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<font class="Apple-style-span" face="Tahoma" size="2">Hi Arthur, </font><div style="font-family: Tahoma; font-size: 10pt; ">thanks for your reply. </div><div><font class="Apple-style-span" face="Tahoma" size="2">From SV experiment in buffer we learned that we thus far deal with a ~600 kd oligomer, however the protein only weakly associates and forms a heterogeneous solution. From concentration dependent biochemical activity experiments in buffer and buffer supplemented with ficoll we assume</font><span class="Apple-style-span" style="font-family: Tahoma; font-size: 10pt; "> that Ficoll stabilizes an active oligomeric species. We wanted to directly confirm that this effect is related to the formation of a greater and more homogeneous steady-state population of possibly 600 kD oligomers.</span></div><div>Best</div><div>Titus<br><br><font class="Apple-style-span" face="Tahoma" size="2">Titus M. Franzmann</font><br><font class="Apple-style-span" face="Tahoma" size="2">S. G. Walter Lab</font><br><font class="Apple-style-span" face="Tahoma" size="2">Mol., Cell. and Develop. Biol. Dept.</font><br><font class="Apple-style-span" face="Tahoma" size="2">University of Michigan</font><br><font class="Apple-style-span" face="Tahoma" size="2">4140C Nat. Sci. Bldg</font><br><font class="Apple-style-span" face="Tahoma" size="2">830 N. University Ave.</font><br><font class="Apple-style-span" face="Tahoma" size="2">Ann Arbor, MI 48109-1048</font><br><font class="Apple-style-span" face="Tahoma" size="2">titusfranzmann.wordpress.om</font><br><br><div style="font-family: Tahoma; font-size: 10pt; "><hr id="stopSpelling">CC: rasmb@rasmb.bbri.org<br>From: arthur.rowe@nottingham.ac.uk<br>Subject: Re: [RASMB] AUC in the presence of 100 mg/ml Ficoll70<br>Date: Tue, 2 Aug 2011 18:57:31 +0100<br>To: tmfr@umich.edu<br><br>
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<font color="maroon">Hi Titus<br>
<br>
The first thing that occurs to me is "how big is your protein/whatever, and what are you trying to find out? Also - have you tried simply putting your system into 100 mg/ml Ficol? I ask because although it is advertised (I am sure correctly) as having "low toxicity", my own experience (many years ago) with trying to fractionate muscle filaments in Ficol was that this solvent was not exactly benign towards my precious samples!<br>
<br>
Obviously in SV the Ficol 70 will sediment, and although it will be invisible (give or take a bit of turbidity) in the u/v, you will get some very weird Johnston-Ogston effects if the s values of your system coincide at all closely with those of the Ficol. Even if your reference channel contained the 100 mg/ml Ficol, you could still have problems. SE sounds at least as problematic - and although you would not be plagued by things such as Johnston-Ogston effects, non-ideality/crowding effects sound daunting.<br>
<br>
Kind regards<br>
<br>
Arthur<br>
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On Aug 2, 2011, at 14:26, Titus M. Franzmann wrote:<br>
<br>
<div class="ecxEmailQuote"><font size="+1">Hi,</font></div>
<div class="ecxEmailQuote"><font size="+1">I was wondering if anyone could comment on whether there is a (proper) way to perform either AUC SV (preferred) or EQ with 100 mg/ml Ficoll70 in the buffer and which would be the best way to analyze such data.</font></div>
<div class="ecxEmailQuote"><font size="+1">Thanks for your assistance.</font></div>
<div class="ecxEmailQuote"><font size="+1">Titus</font></div>
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Arthur J Rowe<br>
Professor of Biomolecular Technology / Director NCMH Business Centre<br>
School of Biosciences<br>
University of Nottingham<br>
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