Anisotropic B-factors can be shown as ellipsoids, with ellipsoid axes and radii representing the eigenvectors and eigenvalues of the atomic mean-square displacement matrix. Anisotropic B-factors are read from the input coordinate file (for example, from ANISOU records in a PDB file) and can be displayed with the tool Thermal Ellipsoids or the command aniso. The figure shows ellipsoids scaled to enclose 50% probability for the heme and nearby atoms from PDB entry 1a6m.

Peroxiredoxins are enzymes that help cells cope with stressors such as high levels of reactive oxygen species. The image shows a decameric peroxiredoxin from human red blood cells (Protein Data Bank entry 1qmv), styled as a holiday wreath.

See also the RBVI holiday card gallery.

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