Figure 2 - full size



	Figure 2 - full size

Figure 2.
FIG. 2. Overall fold and quaternary structure. A, ribbon representation of the UMPKeco monomer fold (using the UMP-containing complex). -strands (yellow) and helices (blue, except 3, pink) are numbered. A stick model of UMP is shown in magenta. The cross-talk loop (green) is labeled CT. The loops are smoothed for clarity. A gray line connects residues that delimit a segment in which no clear density can be seen. B, the dimer constituted by the two molecules of an asymmetric unit. View along the non-crystallographic two-fold axis (indicated by a black ellipse symbol). The blue subunit orientation is close to that in panel A. C, ribbon representation of the hexamer viewed along the three-fold crystallographic axis (indicated by a black triangle). A particular color is used for each subunit. For the blue and green dimer, 3 helices are pink. Corey-Pauling-Koltun space-filling models of UMP are magenta. The three non-crystallographic two-fold axes are shown by dotted lines; they are perpendicular to the three-fold axis. D, magnification of the dimer-dimer interface emphasizing the 2 residues (shown in sticks and labeled) from the cross-talk loop that interact both with their homologues from the facing dimer and with UMP (stick model with carbon atoms in magenta). Hydrogen bonds are shown as red dots. -helices are transparized for clarity. The figure was drawn with PyMOL, Version 0.97 (38).