Elaine,

In UCSF Chimera, when I try to find all the atoms within 4A of a selected residue using the Zone tool, it selects several atoms around that residue. However, I am not able to understand which atom of the selected residue was taken as the reference point for calculating the distances. Please help.

--
Prathvi Singh,
Research Fellow,
Department of Biological Sciences & Bioengineering,
Indian Institute of Technology, Kanpur-208016