Chimera provides a graphical interface to running the program Modeller, either locally or via a web service hosted by the UCSF RBVI. Two types of calculations are available:

• Comparative (homology) modeling. Theoretical models of a protein target are generated using at least one known related template structure and a target-template sequence alignment. There are several ways to generate these inputs in Chimera. See also the Comparative Modeling tutorial.
  
  
• Building parts of a protein without using a template. Missing segments can be built de novo, or existing segments refined by generating additional possible conformations.

Thermosomes are hollow balls inside which proteins are folded. They are found in the cytosol of eukaryotes and in archaea. Eukaryotic thermosomes have 8 different protein subunits, while archaeal ones are composed of one, two or three different proteins. The one shown from Thermoplasma acidophilum has two distinct proteins colored blue and yellow, each present in 8 copies. The two proteins have 60% sequence identity and are very similar in structure. One monomer is shown as a ribbon. Actin and tubulin are folded by eukaryotic thermosomes.

Protein Data Bank model 1a6d.