Hi Peter,<div><br></div><div>may be I&#39;m missing something but I think all you need to do is to place (add to PDB file) a Zn2+ into a blob of density that you believe that Zn belongs to, and then most of refinement tools will take care of it automatically. So I&#39;m not seeing why you need &quot;files for a Zn atom ...&quot;. I guess the task is as simple as I just wrote, isn&#39;t it? </div>
<div><br></div><div>If for some reasons you need to define the harmonic bond restraints between that Zn and surrounding atoms that coordinate it (to enforce coordination geometry), then I&#39;m sure you can do it in Refmac, and phenix.refine let&#39;s you do this too in numerous ways.</div>
<div><br></div><div>Pavel</div><div><br><div class="gmail_quote">On Fri, May 4, 2012 at 11:27 AM, Peter Hsu <span dir="ltr">&lt;<a href="mailto:[log in to unmask]" target="_blank"><a href="/cgi-bin/wa-jisc.exe?LOGON=A3%3Dind1205%26L%3DCCP4BB%26E%3Dquoted-printable%26P%3D2386427%26B%3D--14dae9340859c74aae04bf50a4d0%26T%3Dtext%252Fhtml%3B%2520charset%3DISO-8859-1%26pending%3D" target="_parent" >[log in to unmask]</a></a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi all,<br>
<br>
Forgive the rather ignorant question, but I&#39;m rather new to using coot/model building and I&#39;m trying to model in a Zn2+ atom but coot doesn&#39;t seem to have the files for a Zn atom in its database. I&#39;m not sure where to start looking/how to write a file that defines a Zn2+ atom and to have it properly coordinated by the Cys residues. Can anyone give me any pointers?<br>

<br>
Thanks in advance for the help,<br>
<br>
Peter<br>
</blockquote></div><br></div>