Fig 8. Active site in the ADP-CDP-Gd³⁺ complex.

(A) Binding site of ADP and CDP. Possible interactions are shown as dashed lines. Numbers are the distances shown in Å. The Gd³⁺ ion is shown as magenta sphere. (B) Superimposition of the active site of the ADP-CDP-Gd³⁺ complex (light orange) with that of the CMP "closed" complex (light green). Note that the side chain of Leu195 is omitted from panel B because they occupy the position of the adenine ring of ADP (see Fig 7C). Superscripts L and N denote the residues from the LID and NMP-binding domains. Asterisks represent the residues whose main-chain amide groups are involved in ligand recognition. Arrows represent shifts of the side chains.