<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7652.24">
<TITLE>Small peptides and AUC</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/rtf format -->
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Hello All,</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Following on from discussions of 90 % DMSO,etc. There are more applications (at least through the NCMH) to look at peptides in membranes and detergents, and talking to people in the AUC field, this is a somewhat growing field as people become less fearful of membrane-bound stuff. At this juncture I think it would be good if we could start a discussion strand of what to watch out for when analysing these samples. Original references very welcome.</FONT></SPAN></P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Here's several very obvious things to get us started.</FONT></SPAN>
</P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">1) vbar. The bouyancy of the peptide changes with binding of lipids and detergent. This has to be either (a) matched out by having a solvent that has the same density as the lipid/detergent or (b) calculated from the density increment. I also had a referee once ask me years ago whether I had corrected for charge on a small peptide. The answer was "no" as the peptide was actually a reasonably sized protein, but the original reference for this would be good.</FONT></SPAN></P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">2) Speed. Peptides are small, you will need probably the highest speed possible to analyse them, and for the XL-A/I that's 60K and the associated problem of buying the correct centrepieces (Aluminium or SpinAnalyticals SedVel60K). </FONT></SPAN></P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">3) Co-sedimentation of the solvent. Peptides are small, therefore have low S values. I seem to recall that Na<SUP>+</SUP> sediments at around 0.3 S, therefore you will need to think about how the sedimentation of your solvent components affect the sedimentation of your sample. Not trivial if these affect the solubility and stability of your peptide.</FONT></SPAN></P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">4) Small S values. Are our algorithms good enough?</FONT></SPAN>
</P>
<BR>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Enjoy!</FONT></SPAN>
</P>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Dave.</FONT></SPAN>
</P>
<BR>
<BR>
<P><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Dr. David J. Scott</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Lecturer in Physical Biochemistry</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">National Centre for Macromolecular Hydrodynamics</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">School of Biosciences</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">University of Nottingham</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Sutton Bonington Campus</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Sutton Bonington</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">Leicestershire</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">LE12 5RD</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">United Kingdom</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">dj.scott@nottingham.ac.uk</FONT></SPAN>
<BR><SPAN LANG="en-gb"></SPAN><A HREF="file://www.nottingham.ac.uk/ncmh"></FONT></U></SPAN><SPAN LANG="en-gb"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Georgia">www.nottingham.ac.uk/ncmh</A><SPAN LANG="en-gb"></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">+44 (0) 115 951 6221 Phone</FONT></SPAN>
<BR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Georgia">+44 (0) 115 951 6142 Fax</FONT></SPAN>
</P>
</BODY>
<br/>
<p>
This message has been checked for viruses but the contents of an attachment
may still contain software viruses, which could damage your computer system:
you are advised to perform your own checks. Email communications with the
University of Nottingham may be monitored as permitted by UK legislation.
</p>
</HTML>