An Archaeal Homolog of Proteasome Assembly Factor Functions as a Proteasome Activator (original) (raw)
Figure 3
PbaB forms a homotetramer exhibiting tentacle-like C-terminal segments.
(A) Stereo ribbon model of the PbaB monomer. β-strands, α-helices, and loops are shown in magenta, yellow, and gray, respectively. (B) Ribbon models of the PbaB tetramer are shown on the left and right. The two structures are related by a rotation of 90° around a horizontal axis. Chains A, B, C, and D are colored yellow, green, cyan, and magenta, respectively. The β-hairpin (β4–β5) makes a three-stranded anti-parallel β-sheet with β11 from the adjoining molecule (β11 of chain A and β4–β5 of chain D are highlighted). The non-crystallographic vertical fourfold axis is shown as a black square.