Composite map: select only voxels within a range of resolution?

Hi! I recently processed a cryo-EM map using icosahedral symmetry, achieving a decent global resolution. Then, using localized reconstruction, I improved the resolution of the asymmetric unit (ASU). However, some regions of the ASU still showed poor connectivity. To address this, I generated several additional localized reconstructions, focusing on specific regions of the ASU (taking advantage of the 2-fold, 3-fold, and 5-fold symmetry axes) to improve their local resolution. Now, I want to create a composite map in Chimera by combining the best-resolved regions from each localized reconstruction. However, instead of simply using the voxel-wise maximum density values (as done with vop max), I would like to select voxels based on the best local resolution — i.e., for each voxel position, use the value from the map where that voxel has the highest resolution (lowest local resolution value), as indicated by the associated local resolution maps. Is this type of composite map creation — resolution-guided voxel selection — possible in Chimera (or ChimeraX)? Thanks in advance! Samuel L. Guimarães Aviso Legal: Esta mensagem e seus anexos podem conter informações confidenciais e/ou de uso restrito. Observe atentamente seu conteúdo e considere eventual consulta ao remetente antes de copiá-la, divulgá-la ou distribuí-la. Se você recebeu esta mensagem por engano, por favor avise o remetente e apague-a imediatamente. Disclaimer: This email and its attachments may contain confidential and/or privileged information. Observe its content carefully and consider possible querying to the sender before copying, disclosing or distributing it. If you have received this email by mistake, please notify the sender and delete it immediately.

Hi Samuel, In general it is better to use ChimeraX as it is being developed and may get new features, whereas Chimera is no longer being developed. However, neither Chimera nor ChimeraX has the specific capability that you are asking about. However, please see this recent discussion on how to create composite maps when the parts are of different resolutions or quality -- some users suggested Phenix or TEMPyReFF: <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Jun 12, 2025, at 9:30 AM, Samuel Leite Guimaraes via Chimera-users <chimera-users@cgl.ucsf.edu> wrote:
Hi! I recently processed a cryo-EM map using icosahedral symmetry, achieving a decent global resolution. Then, using localized reconstruction, I improved the resolution of the asymmetric unit (ASU). However, some regions of the ASU still showed poor connectivity. To address this, I generated several additional localized reconstructions, focusing on specific regions of the ASU (taking advantage of the 2-fold, 3-fold, and 5-fold symmetry axes) to improve their local resolution. Now, I want to create a composite map in Chimera by combining the best-resolved regions from each localized reconstruction. However, instead of simply using the voxel-wise maximum density values (as done with vop max), I would like to select voxels based on the best local resolution — i.e., for each voxel position, use the value from the map where that voxel has the highest resolution (lowest local resolution value), as indicated by the associated local resolution maps. Is this type of composite map creation — resolution-guided voxel selection — possible in Chimera (or ChimeraX)? Thanks in advance! Samuel L. Guimarães

[heart] Samuel Leite Guimaraes reacted to your message: ________________________________ From: Elaine Meng <meng@cgl.ucsf.edu> Sent: Thursday, June 12, 2025 8:49:09 PM To: Samuel Leite Guimaraes <samuel.guimaraes@lnbio.cnpem.br> Cc: chimera-users@cgl.ucsf.edu <chimera-users@cgl.ucsf.edu> Subject: Re: [Chimera-users] Composite map: select only voxels within a range of resolution? [Geralmente, você não obtém emails de meng@cgl.ucsf.edu. Saiba por que isso é importante em https://aka.ms/LearnAboutSenderIdentification ] Hi Samuel, In general it is better to use ChimeraX as it is being developed and may get new features, whereas Chimera is no longer being developed. However, neither Chimera nor ChimeraX has the specific capability that you are asking about. However, please see this recent discussion on how to create composite maps when the parts are of different resolutions or quality -- some users suggested Phenix or TEMPyReFF: <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Jun 12, 2025, at 9:30 AM, Samuel Leite Guimaraes via Chimera-users <chimera-users@cgl.ucsf.edu> wrote:
Hi! I recently processed a cryo-EM map using icosahedral symmetry, achieving a decent global resolution. Then, using localized reconstruction, I improved the resolution of the asymmetric unit (ASU). However, some regions of the ASU still showed poor connectivity. To address this, I generated several additional localized reconstructions, focusing on specific regions of the ASU (taking advantage of the 2-fold, 3-fold, and 5-fold symmetry axes) to improve their local resolution. Now, I want to create a composite map in Chimera by combining the best-resolved regions from each localized reconstruction. However, instead of simply using the voxel-wise maximum density values (as done with vop max), I would like to select voxels based on the best local resolution — i.e., for each voxel position, use the value from the map where that voxel has the highest resolution (lowest local resolution value), as indicated by the associated local resolution maps. Is this type of composite map creation — resolution-guided voxel selection — possible in Chimera (or ChimeraX)? Thanks in advance! Samuel L. Guimarães
Aviso Legal: Esta mensagem e seus anexos podem conter informações confidenciais e/ou de uso restrito. Observe atentamente seu conteúdo e considere eventual consulta ao remetente antes de copiá-la, divulgá-la ou distribuí-la. Se você recebeu esta mensagem por engano, por favor avise o remetente e apague-a imediatamente. Disclaimer: This email and its attachments may contain confidential and/or privileged information. Observe its content carefully and consider possible querying to the sender before copying, disclosing or distributing it. If you have received this email by mistake, please notify the sender and delete it immediately.

Thank you very much, Elaine! I´ll take a look! Samuel L. Guimarães ________________________________ De: Elaine Meng <meng@cgl.ucsf.edu> Enviado: quinta-feira, 12 de junho de 2025 17:49 Para: Samuel Leite Guimaraes <samuel.guimaraes@lnbio.cnpem.br> Cc: chimera-users@cgl.ucsf.edu <chimera-users@cgl.ucsf.edu> Assunto: Re: [Chimera-users] Composite map: select only voxels within a range of resolution? [Geralmente, você não obtém emails de meng@cgl.ucsf.edu. Saiba por que isso é importante em https://aka.ms/LearnAboutSenderIdentification ] Hi Samuel, In general it is better to use ChimeraX as it is being developed and may get new features, whereas Chimera is no longer being developed. However, neither Chimera nor ChimeraX has the specific capability that you are asking about. However, please see this recent discussion on how to create composite maps when the parts are of different resolutions or quality -- some users suggested Phenix or TEMPyReFF: <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Jun 12, 2025, at 9:30 AM, Samuel Leite Guimaraes via Chimera-users <chimera-users@cgl.ucsf.edu> wrote:
Hi! I recently processed a cryo-EM map using icosahedral symmetry, achieving a decent global resolution. Then, using localized reconstruction, I improved the resolution of the asymmetric unit (ASU). However, some regions of the ASU still showed poor connectivity. To address this, I generated several additional localized reconstructions, focusing on specific regions of the ASU (taking advantage of the 2-fold, 3-fold, and 5-fold symmetry axes) to improve their local resolution. Now, I want to create a composite map in Chimera by combining the best-resolved regions from each localized reconstruction. However, instead of simply using the voxel-wise maximum density values (as done with vop max), I would like to select voxels based on the best local resolution — i.e., for each voxel position, use the value from the map where that voxel has the highest resolution (lowest local resolution value), as indicated by the associated local resolution maps. Is this type of composite map creation — resolution-guided voxel selection — possible in Chimera (or ChimeraX)? Thanks in advance! Samuel L. Guimarães
Aviso Legal: Esta mensagem e seus anexos podem conter informações confidenciais e/ou de uso restrito. Observe atentamente seu conteúdo e considere eventual consulta ao remetente antes de copiá-la, divulgá-la ou distribuí-la. Se você recebeu esta mensagem por engano, por favor avise o remetente e apague-a imediatamente. Disclaimer: This email and its attachments may contain confidential and/or privileged information. Observe its content carefully and consider possible querying to the sender before copying, disclosing or distributing it. If you have received this email by mistake, please notify the sender and delete it immediately.

Dear colleagues, I would like to know how to solve a problem that I encountered several times in ChimeraX , which is a disruption of beta strands. I attach a figure. This is a beta-hairpin of a model that ChimeraX showed as a coil, but previous data showed that this region corresponds to a beta-hairpin. I imposed a beta-strand fold for each of the corresponding segments with ChimeraX (setattr #3/a:40-52,59-66) res ss_type 0) but the strands appear interrupted between consecutive residues. I guess it's a problem of the polypeptide bond, but nevertheless Chimera can solve the problem. How can I solve this in ChimeraX? Thank you for your time and best regards, Maria -- Maria Solà Dep. Structural Biology IBMB-CSIC Barcelona Science Park (Helix Building) Baldiri Reixac 15 08028 BARCELONA Spain Tel: (+34) 93 403 4950 <http://linkedin.com/company/ibmb> <https://twitter.com/IBMB_CSIC> <https://www.instagram.com/ibmb_csic_/> <https://www.facebook.com/IBMB.CSIC.es>

Hi Maria, For ChimeraX questions, it is better to use the chimerax-users@cgl.ucsf.edu <mailto:chimerax-users@cgl.ucsf.edu> address CC'd here. The chimera-users address is for Chimera and we don't want people to get confused between the two. In ChimeraX: Probably you also need to set ss_id to indicate they are all in the same strand, instead of two consecutive strands, which would always be shown with a short connector instead of as a continuous strand. Please see <https://rbvi.ucsf.edu/chimerax/docs/user/attributes.html#residue> ... and previous posts, such as these talking about helices but probably the same problem as your strands: <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> <https://mail.cgl.ucsf.edu/mailman/archives/list/chimerax-users@cgl.ucsf.edu/...> I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Chimera(X) team Resource for Biocomputing, Visualization, and Informatics Department of Pharmaceutical Chemistry University of California, San Francisco
On Jun 29, 2025, at 8:02 AM, Maria Sola i Vilarrubias <maria.sola@ibmb.csic.es> wrote:
Dear colleagues,
I would like to know how to solve a problem that I encountered several times in ChimeraX , which is a disruption of beta strands. I attach a figure. This is a beta-hairpin of a model that ChimeraX showed as a coil, but previous data showed that this region corresponds to a beta-hairpin. I imposed a beta-strand fold for each of the corresponding segments with ChimeraX (setattr #3/a:40-52,59-66) res ss_type 0) but the strands appear interrupted between consecutive residues. I guess it's a problem of the polypeptide bond, but nevertheless Chimera can solve the problem. How can I solve this in ChimeraX?
Thank you for your time and best regards, Maria
-- Maria Solà Dep. Structural Biology IBMB-CSIC Barcelona Science Park (Helix Building) Baldiri Reixac 15 08028 BARCELONA Spain Tel: (+34) 93 403 4950
participants (3)
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Elaine Meng
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Maria Sola i Vilarrubias
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Samuel Leite Guimaraes