<html xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv=Content-Type content="text/html; charset=us-ascii">
<meta name=Generator content="Microsoft Word 11 (filtered medium)">
<style>
<!--
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:purple;
text-decoration:underline;}
p
{mso-margin-top-alt:auto;
margin-right:0cm;
mso-margin-bottom-alt:auto;
margin-left:0cm;
font-size:12.0pt;
font-family:"Times New Roman";}
span.StileMessaggioDiPostaElettronica18
{mso-style-type:personal-reply;
font-family:Arial;
color:navy;}
@page Section1
{size:595.3pt 841.9pt;
margin:70.85pt 2.0cm 2.0cm 2.0cm;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=IT link=blue vlink=purple>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=3 color=navy face="Courier New"><span
style='font-size:12.0pt;font-family:"Courier New";color:navy'>Dear Gromacs
users,<o:p></o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>I would like to use
gromacs to simulate a peptide containing a D-proline using the opls force field.
I guess that, considering that L- and D- PRO differs only for chirality, the
two a.a. topologies should little differ, and that an improper torsion and/or
torsional terms should be modified in D-PRO topology with respect to L-PRO, but
I am not sure on how to modify the improper torsion ( it is _C CA N CD in
L-pro) and if it is correct to do so or only torsional terms should be
modified.<o:p></o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Thank you in advance<o:p></o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p style='mso-margin-top-alt:3.75pt;margin-right:0cm;margin-bottom:3.75pt;
margin-left:0cm'><font size=2 color=navy face=Arial><span lang=EN-GB
style='font-size:10.0pt;font-family:Arial;color:navy'>Stefano Pieraccini<o:p></o:p></span></font></p>
</div>
</body>
</html>