Hi Prathvi, You can use selection, then look at the Selection Inspector to see number of residues. For example, command: select :hoh .... or menu: Select... Residues... HOH ...and then open the Selection Inspector by clicking the green magnifying glass at the lower right corner of the Chimera window. The top part of that dialog will say how many residues are selected. See selection <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/selection.html> Selection Inspector <https://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/inspection.html> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Department of Pharmaceutical Chemistry University of California, San Francisco

On Nov 2, 2021, at 3:53 AM, Prathvi Singh via Chimera-users <chimera-users@cgl.ucsf.edu> wrote:

Hi,

Is there a command in UCSF chimera to count the total no. of water molecules in a PDB file? Can we also count, say the total number of alanine residues in a PDB file or any other other residue for that matter?

-- Prathvi Singh, Research Fellow, Department of Biological Sciences & Bioengineering, Indian Institute of Technology, Kanpur-208016 _______________________________________________ Chimera-users mailing list: Chimera-users@cgl.ucsf.edu Manage subscription: https://plato.cgl.ucsf.edu/mailman/listinfo/chimera-users