On Jun 27, 2011, at 11:25 AM, George Tzotzos wrote:

Can anyone provide some help.

I'm trying to select two specific oxygen atoms in different residues (98 and 142).

The command select :142@O1 :98@O1 selects only 1 atom (that of residue 142).

I tried select :98@O1 only. The output is "selection" cleared.

I'm rather puzzled. Any help would be greatly appreciated

Hi George,
Chimera either believes there is no residue 98 in your structure, or that there is no atom named "O1" in that residue.  Try this:

select :98

Does anything get selected?  If that does select a residue, then do this:

label sel

Is there an "O1" among the atoms that get labeled?

--Eric

                        Eric Pettersen

                        UCSF Computer Graphics Lab

                        http://www.cgl.ucsf.edu