Fig. 6.

Nucleotide-binding state of the CCT–mLST8 complex. a Distribution of nucleotide density in the difference map between the yeast AMP–PNP CCT and the human mLST8–CCT reconstructions. Since all the nucleotide-binding sites of the AMP–PNP CCT reconstruction host a nucleotide, density differences (highlighted in red) indicate unoccupied nucleotide-binding pockets in mLST8–CCT complex, and lack of red density indicates the presence of nucleotide in CCT8, CCT8′, CCT6 and partially in CCT6′. b ADP binding site in CCT8. The protein ribbon diagram is shown in tan with residues in close contact with the ADP molecule highlighted as sticks. The ADP is also represented in sticks with carbon in yellow, oxygen in red, nitrogen in blue and phosphorous in orange. Hydrogen bonds are depicted as dashed lines. The map contour level is set at 2.5. The figure was produced with Chimera. c Alignments of the CCT amino-acid sequences adjacent to D499 and Y49 of CCT8 comparing the eight human CCT subunits and CCT6 and CCT8 from different species. Residues identical to D499 of CCT6 and CCT8 and Y49 of CCT8 are highlighted in green. hs Homo sapiens, bt Bos taurus, mm Mus musculus, dm Drosophila melanogaster, sc Saccharomyces cerevisiae