The Structural Basis of ATP as an Allosteric Modulator
The crystal structures of allosteric ATP unbound and bound proteins are shown in pale cyan and dark green, respectively. The relatively large conformational changes in the allosteric ATP unbound and bound proteins are shown in red and orange, respectively, coupled with the residues in light pink and light green, respectively. The adenine in ATP is an allosteric trigger in two cases: (A) P2X4 ion channel (PDB: 4DW0 vs. 4DW1; the former is allosteric ATP unbound structure and the latter is allosteric ATP bound structure); and (B) Aspartate carbamoyltransferase (PDB: 6AT1 vs. 4AT1). The triphosphate part of ATP is an allosteric trigger in eight cases: (C) Cytosolic 5’-nucleotidase II (PDB: 2XCX vs. 2XCW); (D) ClpX (PDB: 3HTE vs. 3HWS); (E) Glycogen phosphorylase (PDB: 1FC0 vs. 1FA9); (F) Ribonucleotide reductase (PDB: 1R1R vs. 3R1R); (G) MutS (PDB: 1E3M vs 1W7A); (H) DnaA (PDB: 1L8Q vs. 2HCB); (I) Phosphofructokinase 1 (PDB: 2PFK vs. 1PFK); (J) Chaperonin GroEL (PDB: 1KP0 vs. 1KP8).