Fig. 3.

(a) Cartoon representation of IPCT monomer. The color scheme is according to the topology diagram shown in panel b. The active site loop is shown as a thicker purple loop herein and after, and citrate is drawn as sticks (carbon is yellow and oxygen red). (b) TOPS-generated topology diagram of IPCT. Relevant secondary structure elements are numbered, and the location of the active site loop is noted with an asterisk. (c) Cartoon and surface representation of IPCT dimer. Chain F is drawn in yellow with the molecular surface; residues at the interface are colored magenta (chain F) and cyan (chain E). (d) Zoomed view at the dimer interface. Residues establishing side chain interactions are displayed. By the atom color code, carbon is yellow for chain F and cyan for chain E, oxygen is red, and nitrogen is dark blue for both chains.