Friends,<br>I am trying to modify the sugar of a nucleotide. I am interested in making a linkage of two carbons in the sugar as in the attached pdb. I tried to use the Build structure -&gt; modify structure option but it does not work in the sense that when i select carbon atom (c2&#39;) and tried to connect it to an oxygen, chimera says that it is already bonded and hence some bonds to create a new one. Is there any way to make such linkages as in the pdb ?<br>
<br>Thanks,<br>Bala<br>