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<P class=MsoNormal>Dear Ariel,</P>
<P class=MsoNormal> <?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /><o:p></o:p></P>
<P class=MsoNormal>I am a big fan of your Segal program because of the
user-friendly feature.<SPAN style="mso-spacerun: yes"> </SPAN>The dynamic
fitting pictures that change in front of your eyes for you to select the best
fitting radius region to use is a great time saver in data analysis.<SPAN
style="mso-spacerun: yes"> </SPAN>In the Beckman Origin program, editing
equilibrium curve in the dark by guessing is no fun.<SPAN
style="mso-spacerun: yes"> </SPAN>I have to edit several radius regions,
one by one, in order to obtain the best variance value so I can have confident
in the result. </P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal>I do a lot of calculation for Ka at various GuHCl
concentrations in order to estimate the free energy of subunit dissociation
using Beckman’s origin program.<SPAN style="mso-spacerun: yes"> </SPAN>I
constantly worry that I am not getting the best apparent molecular weight to use
for Ka calculation.<SPAN style="mso-spacerun: yes"> </SPAN>Lately I have
combined Segal and Origin program, meaning that I apply Segal program to get
what I think is the best fitting radius region, I then reapply this same radius
region to edit the subset from the Beckman Origin program (since your program
can not be used to calculate Ka), thinking that with this combine approach I can
surely get the best reliable MW to use for an accurate Ka. </P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal>However, to my surprise, I do not get the same molecular
weight even if I use exactly the same radius boundary values.<SPAN
style="mso-spacerun: yes"> </SPAN>Of the 4 set of edited subset data I
tested, the discrepancy various from 4 to 14 %.<SPAN
style="mso-spacerun: yes"> </SPAN>Do you know where is this discrepancy
coming from? Is Beckman fitting equation different than the equation you used
for Segal program?<SPAN style="mso-spacerun: yes"> </SPAN>Is 4-14%
discrepancy acceptable?<SPAN style="mso-spacerun: yes"> </SPAN>I think I
can live with 5-6% discrepancy. I am including the raw data 00008.ra1 for anyone
who is interested in looking into this.<SPAN style="mso-spacerun: yes">
</SPAN>I have not included NONLIN in this comparison.</P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal><B><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">Summary: </SPAN></B><SPAN
style="mso-spacerun: yes"> </SPAN>4 set of the edit<B><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt"> </SPAN></B>data from raw
data 00008.ra1</P>
<P class=MsoHeader
style="tab-stops: .5in center 3.0in right 6.0in"> <o:p></o:p></P>
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<TBODY>
<TR>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>Edit
Equilibrium curve<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>Boundary
radius region used<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>MW
obtained from Origin / variance<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 1.5in; mso-border-left-alt: solid windowtext .5pt"
vAlign=top width=144>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>MW
obtained from Segal / correlation<o:p></o:p></I></B></P>
<P align=center class=MsoNormal
style="TEXT-ALIGN: center"> <B><I><o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: windowtext 0.5pt solid; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.6pt; mso-border-left-alt: solid windowtext .5pt"
vAlign=top width=118>
<H3><SPAN style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">Discrepancy@
%<o:p></o:p></SPAN></H3></TD></TR>
<TR>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<H2>Edit 1</H2></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal
style="TEXT-ALIGN: center">6.913-7.148</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">67 KD /
17.1</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 1.5in; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=144>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">59 KD /
0.999458</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.6pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><I><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">12<o:p></o:p></SPAN></I></P></TD></TR>
<TR>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>Edit
2<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal
style="TEXT-ALIGN: center">6.942-7.139</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">66KD /
18.3</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 1.5in; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=144>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">60 KD /
0.999504</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.6pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><I><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">9<o:p></o:p></SPAN></I></P></TD></TR>
<TR>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>Edit
3<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal
style="TEXT-ALIGN: center">6.920-7.139</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">65 KD /
17.8</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 1.5in; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=144>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">56 KD /
0.999322</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.6pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><I><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">14<o:p></o:p></SPAN></I></P></TD></TR>
<TR>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: windowtext 0.5pt solid; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><B><I>Edit
4<o:p></o:p></I></B></P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal
style="TEXT-ALIGN: center">6.897-7.118</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.55pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">56 KD /
13.1</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 1.5in; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=144>
<P align=center class=MsoNormal style="TEXT-ALIGN: center">54 KD /
0.999435</P></TD>
<TD
style="BORDER-BOTTOM: windowtext 0.5pt solid; BORDER-LEFT: medium none; BORDER-RIGHT: windowtext 0.5pt solid; BORDER-TOP: medium none; PADDING-BOTTOM: 0in; PADDING-LEFT: 5.4pt; PADDING-RIGHT: 5.4pt; PADDING-TOP: 0in; WIDTH: 88.6pt; mso-border-left-alt: solid windowtext .5pt; mso-border-top-alt: solid windowtext .5pt"
vAlign=top width=118>
<P align=center class=MsoNormal style="TEXT-ALIGN: center"><I><SPAN
style="FONT-SIZE: 14pt; mso-bidi-font-size: 12.0pt">4<o:p></o:p></SPAN></I></P></TD></TR></TBODY></TABLE>
<P class=MsoNormal>@ (<B><I> MW obtained from Origin<SPAN
style="mso-spacerun: yes"> </SPAN>-<SPAN style="mso-spacerun: yes">
</SPAN>MW obtained from Segal) / MW obtained from Origin<SPAN
style="mso-spacerun: yes"> </SPAN></I></B></P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal>With best regards,</P>
<P class=MsoNormal> <o:p></o:p></P>
<P class=MsoNormal>Chris</P>
<P class=MsoNormal> <o:p></o:p></P></FONT></DIV>
<P><FONT face=Arial
size=2>--------------------------------------------------------------------------</FONT>
<BR><FONT face=Arial size=2>Christopher Chin</FONT> <BR><FONT face=Arial
size=2>Manager, XLA-Analytical Ultracentrifugation facility</FONT> <BR><FONT
face=Arial size=2>Sealy Center for Structural Biology</FONT> <BR><FONT
face=Arial size=2>HBC&G, 5.134 MRB.UTMB, Galveston,Tx 77555-1055</FONT>
<BR><FONT face=Arial size=2>cchin@utmb.edu, 409-772-1693, efax
708-585-1920</FONT> <BR><FONT face=Arial
size=2>---------------------------------------------------------------------------</FONT>
</P><BR>
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