From: UMJ <xuyu@UMDNJ.EDU>
  To  : E.braswell <BRASS@UCONNVM.UCONN.EDU>
  Date: Fri, 28 Apr 2000 15:01:59 -0400

Re: incompetency

In the field of protein folding, 'misfold' usually means a population
transiently misfolded on kinetic time scale, about 100s ms, but not
necessarily in a 'locked in' conformation. This misfold population can
correct themselves and/or different conformations can interconvert to each
other on millisec time scale or faster under native conditions, if they are
to be considered as part of the 'ensemble'. Any differences in conformation
that can be observed in sedimentation equilibrium experiments are more
likely caused by impurity and/or heterogeneity, I think.

Yujia
----- Original Message -----
From: E.braswell <BRASS@UCONNVM.UCONN.EDU>
To: <rasmb@alpha.bbri.org>
Sent: Thursday, April 27, 2000 8:52 PM
Subject: incompetency


> John, I don't know much about folding, or its dynamics, but can't
molecules
> be locked in a number of nearly similar configurations or be "misfolded"
> (as I've heard the term used by people who produce proteins by recombinant
> methods)?   This was what I was thinking of, and a number of such
misfolded
> species could conceivably cause a range of lnKs.
> It would be nice if we could produce a graph of the distribution of lnKs
for
> a given species in solution in order to characterize these.
> I have contributed my 2 cents more on this topic in the last 2 days than I
> usually do in a year--so please bear with me and give us one more John!
> and any others please.
>   Next question, does anyone know if glycosylation can do most of the nice
> things that PEGylation does for pharmaceuticals?  Incidentally, I am
> ignorant of the literature, but I have lately tried estimating degrees
> of PEGylation and glycosylation, by measuring sed velocity with both
> interference and absorption at 280.  I know of some gotchas but there are
> probably more.  Any references anybody?
>                                            Regards, Emory
>
> Emory H. Braswell
> Professor of Biophysics and Head,
> National Analytical Ultracentrifugation Facility
> U-149
> University of Connecticut
> STORRS, CT 06269-3149
> TEL 860 486 5032
> FAX         5005
> E.BRASWELL@UCONN.EDU