1Conservation of archaeal ThsA and human BBS and CCT8L sequences relative to human CCT monomers. Sequence-positions are considered conserved if they are occupied by residue-types appearing in the homologous position in any of the human CCT sequences. Ninety-three intra-ring contact positions and 15 inter-ring contact positions were identified from the thermosome structure (1ad6). Contact positions were defined by a distance of their side-chain heavy atoms of at most 4.0Å from any heavy atom of the nearby monomer in the thermosome structure. For each protein family, the table indicates the number and percentage (in parenthesis) of positions conserved among: all 93 intra-ring contact positions (MM); seventeen intra-ring contact-positions conserved among human CCT monomers (CMM); all 15 inter-ring contact positions, none of which were conserved among CCT monomers (RR). 2Global indicates the range of similarities (percent values) of each sequence to human CCT-subunit proteins within all aligned positions.