I'm a new user.
I wonder how to fuse two proteins by a peptide bond using pymol  ? (from 2 .pdb files into 1 file)
I found the following description in user manual.but I don't know how to select a single atom.
I know it sounds silly, but I really don't know how to do this step.
I  really appreciate your help!



   "fuse" joins two objects into one by forming a bond.  A copy of
   the object containing the first atom is moved so as to form an
   approximately resonable bond with the second, and is then merged
   with the first object.


   fuse (selection1), (selection2)


   cmd.fuse( string selection1="(lb)", string selection2="(lb)" )


   Each selection must include a single atom in each object.
   The atoms can both be hydrogens, in which case they are
   eliminated, or they can both be non-hydrogens, in which
   case a bond is formed between the two atoms.