UCSF ChimeraX

UCSF ChimeraX (or simply ChimeraX) is the next-generation molecular visualization program from the Resource for Biocomputing, Visualization, and Informatics (RBVI), following UCSF Chimera. ChimeraX can be downloaded free of charge for academic, government, nonprofit, and personal use. Commercial users, please see licensing.

ChimeraX development is supported in part by grants from the National Institutes of Health (currently R01-GM129325, previously P41-GM103311).

Feature Highlight

Fitting to Density Maps

Atomic structures and/or maps can be fit rigidly into other maps with the fitmap command. A common use is to locally optimize the fit after initial placement by hand. Options include symmetrical and sequential fitting, as well as global search to generate multiple starting points for local optimization.

Elongator is a highly conserved complex that associates with RNA polymerase II during transcriptional elongation. In the image, one of its six subunits, Elp2 (PDB 5m2n), has been fit into a map of the Elp123 subcomplex (EMDB 4151).

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Example Image

Potassium Channel-Calmodulin Complex

KCNQ1 is the pore-forming subunit of a cardiac potassium channel. It binds to calmodulin, and mutations in either of these proteins can cause congenital long QT syndrome, a dangerous propensity for irregular heartbeats. In the image, a structure of the KCNQ1/calmodulin complex (PDB 5vms) has been assembled into the native tetrameric form with the sym command. The view is from the cytoplasmic side, with KCNQ1 shown as surfaces, calmodulin as cartoons, and calcium ions as balls. A pastel palette from ColorBrewer has been used to color the surfaces, darkened with color modify for the cartoons, and “rotated” 45° in hue for the ions. See the command file colormod.cxc.

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