Hi Christian, We're glad you like the "Write DMS" tool in Chimera! <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/dms.html#writedms> Note that it does not run a surface calculation, but simply converts the molecular surface already shown in Chimera into the DMS format for output. Thus it effectively uses whatever parameters you had used to calculate the molecular surface in Chimera. That is currently done with MSMS (included with Chimera), a different program than DMS with different heuristics, so even with the most similar parameters possible I don't think the dots would be in exactly the same places even though the surfaces would basically coincide. More about molecular surfaces in Chimera: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/representation.html#surfaces

If you used Chimera defaults for surface calculation, the probe radius is the same as the DMS default (1.4 Angstroms), but the atomic radii and dot density are different. The dms man page says the default density gives about 5 dots per square Angstrom. <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/dms1.html> You could set the Chimera molecular surface vertex density to 5 (instead of the default 2) to be similar to the dms default. To change an existing surface, Ctrl-click to select it and then for "MSMS surface" in the Selection Inspector (Actions... Select) change the "vertex density" value. If you want to change the Chimera defaults so that future surfaces will be created with that density, choose Favorites... Preferences, go to the "New Surfaces" category, change the value, click Save. <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/preferences.html#New%20Surfa...

Default atomic radii in Chimera: <http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/vdwrad.html> I don't believe the old DMS default radii are necessarily better than the Chimera default atomic radii, but if you really wanted to set the radii in Chimera to these values, it can be done with the "Define Attribute" tool or the command "defattr" along with the attribute assignment file dmsrad.txt attached below (it is a very small, simple text file). <http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/defineattrib/define...

I personally favor having Write DMS as a separate tool from Dock Prep because I think people should display the surface, adjust which part is displayed (since there is a nice option to only write what is displayed), and possibly change the surface calculation parameters rather than clicking a single button on Dock Prep to just do everything and write the whole surface without tailoring it to the situation. Best, Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html

From: Christian Schudoma <schudoma@mpimp-golm.mpg.de> Date: October 2, 2008 5:48:57 AM PDT To: "dock-fans@docking.org" <dock-fans@docking.org> Subject: Re: [Dock-fans] DMS replacement

I think WriteDMS is a very nice new feature for Chimera. Does it run with the same default parameters as the original dms?

Also, I wonder if it would be possible to integrate WriteDMS into the DockPrep tool? Maybe add an option there to run surface generation and WriteDMS automatically when DockPrepping a molecule?

Thanks & best regards, Christian