[RASMB] sedimentation velocity data

[John Philo]

Anamika, your attachment did not come through, but most likely this is not a
radial calibration problem. Assuming the apparent positions of the sample
and reference meniscus are moving to higher radius over time, that would be
consistent with a slow leak (probably the red fill-hole gaskets have not
produced a complete vacuum seal). If you search through the archives you
will find discussions about such problems and alternatives to the red
gaskets from Beckman.
 
Without seeing the data it is hard to say much about the impact on the data
analysis, but definitely any leakage of the sample could significantly
impact the sedimentation coefficients and the detection of minor components.
You may be able to minimize the impact by fitting for the meniscus position,
and if all you are trying to do is to distinguish whether your main species
is a monomer versus dimer that conclusion would likely be valid, but sorry,
I probably wouldn't trust this experiment for any critical results.
 
John
  _____  

From: rasmb-bounces at rasmb.bbri.org [mailto:rasmb-bounces at rasmb.bbri.org] On
Behalf Of Anamika Patel
Sent: Friday, September 30, 2011 8:01 AM
To: RASMB at rasmb.bbri.org
Subject: [RASMB] sedimentation velocity data


Dear RASMB subscribers,
 
We collected some sedimentation velocity data on AUC (XLA) and happed to
notice a problem with our mechine with radial cabritation. As a result of
that in our data the sample as well as refrence mesicuse drifted a lot from
scan to scan. It seems that we need some fixing with our AUC but meanwhile I
was wondering if there is any way to analyze the data which I have already
collected. I have atatched a snapshot of my data. Any suggestions or advice
would be highly appreciated.
 
Thanks
 
 
Anamika Patel, Ph.D.
Department of Biology
Life Science Complex
Syracuse University
107 College place
Syracuse- 13244
NY
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