On Tue, Feb 15, 2011 at 2:07 PM, Jason Vertrees <jason.vertrees@schrodinger.com> wrote:
Interesting question.  PyMOL's wildcards can help here:

select allButInsertionsA, not (i. *A)

This will look for all residue NUMBERS that end in "A" and select
everything but that.

Thanks, that definitely helps a lot.  I just realized that my original question was poorly formulated, however: the insertion code often (maybe always?) changes from residue to residue (PDB ID 3edx is one example).  So I could build up a list of all insertion codes, or just use all uppercase characters, but I'm worried about the size of the resulting selection strings.  (I managed to crash PyMOL for the first time in years last week with a very long selection.)  Can I instead select for a *blank* insertion code?