[RASMB] Sedimentation of rods

[John Philo]

Tom, I don't think your recollection of a constant value of ~2.7 S is
correct in general for protein rods. For very long rods (high length to
diameter ratios) the sedimentation coefficient does become independent of
length, but the sedimentation coefficient value will be determined by the
buoyant mass per unit length, which of course depends strongly on the rod
diameter. 
 
I did once run velocity on some carbon nanotubes, but due to this very weak
length dependence it provides very poor separation by length. 
 
SEDNTERP will of course calculate length/diameter ratios for shorter rods
(cylinders) out to ratios of about 10. 
 
John

  _____  

From: rasmb-bounces at list.rasmb.org [mailto:rasmb-bounces at list.rasmb.org] On
Behalf Of Laue, Thomas
Sent: Thursday, May 08, 2014 8:42 AM
To: RASMB List ?[rasmb at list.rasmb.org]?
Subject: [RASMB] Sedimentation of rods


Hi all-
We are looking at a protein that forms rods. I have little background on
systems like this, and am looking for some guidance. In particular, my
recollection is that for long rods, as the rod length increases, the s
collapses back to a constant ~2.7 s. 
Any wisdom will be welcome.
Best wishes,
Tom

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20140508/23aab04c/attachment.htm>