On Feb 7, 2012, at 11:13 AM, Elaine Meng wrote:

This approach requires using the minimize command and its "fragment" option, only available in the command (not GUI), and in fairly recent builds of Chimera 1.6.

In fact there is a bug in AddCharge in the most recent build that will trip you up with the 1a6m structure.  The bug is fixed now and will be in the next successful build.

--Eric

                        Eric Pettersen

                        UCSF Computer Graphics Lab

                        http://www.cgl.ucsf.edu