Hi Careina,<br><br><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div><div style="font-family:&#39;times new roman&#39;, &#39;new york&#39;, times, serif;font-size:12pt">
<div>I just have a slight concern regarding my Rwork Rfree difference. I have a structure that I have solved. I am reasonably content that it is complete because it has refined well, it no longer has bad geometries and contacts and all the rotamers, ramachandra, bond lengths etc are good. It gives favourable scores on molprobity and procheck. My only concern is the R factor difference. The resolution of the structure is 2.3A. The R factor is 0.24 after refinement but the Rfree is 0.33 which seems to me to be rather high. Should I be concerned?</div>
</div></div></blockquote><div><br></div><div>looking at all similar to yours structures in PDB (*):</div><div><br></div><div><div>phenix.r_factor_statistics 2.3</div><div><br></div><div><br></div><div>Histogram of Rwork for models in PDB at resolution 2.20-2.40 A:</div>
<div>     0.126 - 0.147      : 29</div><div>     0.147 - 0.168      : 253</div><div>     0.168 - 0.189      : 958</div><div>     0.189 - 0.210      : 1649</div><div>     0.210 - 0.232      : 1440</div><div>     0.232 - 0.253      : 549 &lt;&lt;&lt; your structure</div>
<div>     0.253 - 0.274      : 125</div><div>     0.274 - 0.295      : 12</div><div>     0.295 - 0.316      : 1</div><div>     0.316 - 0.337      : 4</div><div>Histogram of Rfree for models in PDB at resolution 2.20-2.40 A:</div>
<div>     0.165 - 0.188      : 31</div><div>     0.188 - 0.211      : 223</div><div>     0.211 - 0.235      : 860</div><div>     0.235 - 0.258      : 1733</div><div>     0.258 - 0.281      : 1508</div><div>     0.281 - 0.304      : 542</div>
<div>     0.304 - 0.328      : 97</div><div>     0.328 - 0.351      : 19 &lt;&lt;&lt; your structure</div><div>     0.351 - 0.374      : 6</div><div>     0.374 - 0.397      : 1</div><div>Histogram of Rfree-Rwork for all model in PDB at resolution 2.20-2.40 A:</div>
<div>     0.001 - 0.011      : 53</div><div>     0.011 - 0.021      : 172</div><div>     0.021 - 0.031      : 524</div><div>     0.031 - 0.041      : 960</div><div>     0.041 - 0.050      : 1264</div><div>     0.050 - 0.060      : 1050</div>
<div>     0.060 - 0.070      : 592</div><div>     0.070 - 0.080      : 224</div><div>     0.080 - 0.090      : 114 </div><div>     0.090 - 0.100      : 67 &lt;&lt;&lt; your structure</div><div>Number of structures considered: 5020</div>
</div><div><br></div><div>(*): <span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; "><b>Crystallographic model quality at a glance</b>. <span class="SpellE">Acta</span> <span class="SpellE">Cryst</span>. D65, 297-300</span></div>
<div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; "><br></span></div><div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; ">It seems like you should be concerned about the high Rfree and Rfree-Rwork.</span></div>
<div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; "><br></span></div><div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; ">The second question about how to address it is program specific in some sense and I hope Refmac experts will address it.</span></div>
<div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; "><br></span></div><div><span class="Apple-style-span" style="font-family: verdana, helvetica, arial, sans-serif; font-size: 14px; ">Pavel.</span></div>
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