
Dear Chimera experts, I’ve got a system of three interacting proteins, and each of them is missing some linker regions in the crystal structure. I’ve succesfully used the Modeller interface in Chimera to add these regions, but the problem I’m facing now is that it adds the residues without considering that other atoms from another protein of the system are in the way. Is there a way to tell Modeller to be sensitive to other structures nearby? Thanks for any comments, [Imperial College London] <http://www.icb-cdt.co.uk/> Juan Eiros Zamora / PhD Student je714@ic.ac.uk<mailto:je714@ic.ac.uk> / +44 (0) 7783018326 Imperial College London Imperial College Road SW7 2AZ | UK http://www.icb-cdt.co.uk/

Hi Juan, Sorry no, not with the Chimera Modeller interface. Modeling a multimer or complex (taking into account other chains) requires running Modeller outside of Chimera, a harder task if you don’t have experience doing that already. <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/multalignviewer/modeller.html> I don’t know if your initial model was from comparative modeling or just filling in missing segments without a template. Either way, you could try generating multiple conformations and seeing if any of them are better at avoiding the other proteins. If the initial model is from comparative modeling, you could subsequently use the loop remodeling interface and just get ensembles of new conformations for the problematic segments, in the same way as modeling missing segments. I.e., increase “number of output models” to give yourself a larger sample of conformations and see if any of them make more sense relative to the whole complex. It will still ignore the other chains, but you will have more possibilities to choose from. Other than that, you could always try rotating bonds yourself, but that’s generally a combinatorial problem not well solved by interactive human tweaking. (There is minimization too, but it generally has very limited ability to fix structure problems with a rugged energy landscape.) <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html#adjust> I hope this clarifies, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco
On May 26, 2016, at 8:55 AM, Eiros Zamora, Juan <j.eiros-zamora14@imperial.ac.uk> wrote:
Dear Chimera experts,
I’ve got a system of three interacting proteins, and each of them is missing some linker regions in the crystal structure.
I’ve succesfully used the Modeller interface in Chimera to add these regions, but the problem I’m facing now is that it adds the residues without considering that other atoms from another protein of the system are in the way.
Is there a way to tell Modeller to be sensitive to other structures nearby?
Thanks for any comments,
Juan Eiros Zamora / PhD Student

Thanks for the suggestion, I’ll take a look at doing it directly through the Modeller program. Best, Juan
On 26 May 2016, at 17:12, Elaine Meng <meng@cgl.ucsf.edu> wrote:
Hi Juan, Sorry no, not with the Chimera Modeller interface. Modeling a multimer or complex (taking into account other chains) requires running Modeller outside of Chimera, a harder task if you don’t have experience doing that already.
<http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/multalignviewer/modeller.html>
I don’t know if your initial model was from comparative modeling or just filling in missing segments without a template. Either way, you could try generating multiple conformations and seeing if any of them are better at avoiding the other proteins. If the initial model is from comparative modeling, you could subsequently use the loop remodeling interface and just get ensembles of new conformations for the problematic segments, in the same way as modeling missing segments. I.e., increase “number of output models” to give yourself a larger sample of conformations and see if any of them make more sense relative to the whole complex. It will still ignore the other chains, but you will have more possibilities to choose from.
Other than that, you could always try rotating bonds yourself, but that’s generally a combinatorial problem not well solved by interactive human tweaking. (There is minimization too, but it generally has very limited ability to fix structure problems with a rugged energy landscape.) <http://www.rbvi.ucsf.edu/chimera/docs/ContributedSoftware/editing/editing.html#adjust>
I hope this clarifies, Elaine ---------- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco
On May 26, 2016, at 8:55 AM, Eiros Zamora, Juan <j.eiros-zamora14@imperial.ac.uk> wrote:
Dear Chimera experts,
I’ve got a system of three interacting proteins, and each of them is missing some linker regions in the crystal structure.
I’ve succesfully used the Modeller interface in Chimera to add these regions, but the problem I’m facing now is that it adds the residues without considering that other atoms from another protein of the system are in the way.
Is there a way to tell Modeller to be sensitive to other structures nearby?
Thanks for any comments,
Juan Eiros Zamora / PhD Student
participants (2)
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Eiros Zamora, Juan
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Elaine Meng