Pyruvate phosphate dikinase: Difference between revisions
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3. PPDK-His~P<sub>2</sub>O<sub>7</sub> + AMP ⇄ PPDK-His + ATP | 3. PPDK-His~P<sub>2</sub>O<sub>7</sub> + AMP ⇄ PPDK-His + ATP | ||
# | #PPDK-His + PEP ⇄ PPDK-His~PO<sub>3</sub> + pyruvate | ||
# | #PPDK-His~PO<sub>3</sub> + P<sub>2</sub>O<sub>7</sub> ⇄ PPDK-His~P<sub>2</sub>O<sub>7</sub> + PO<sub>3</sub> | ||
# | #PPDK-His~P<sub>2</sub>O<sub>7</sub> + AMP ⇄ PPDK-His + ATP | ||
The enzyme contains two remotely located reaction centers ~45 Å apart; the PEP/pyruvate partial reaction (step 1) takes place at the C-terminal domain (adopting an α/β barrel fold) and the nucleotide and inorganic phosphate partial reactions (steps 2 and 3) take place at the N-terminal domain (adopting the ATP grasp fold with two sub domains). A central domain, tethered to the N- and C-terminal domains by two closely-associated linkers, contains a phosphorylatable histidine residue (His455). To shuttle the phosphoryl group between the two reaction centers, the His-domain undergoes a ~110° swivel motion around the two linkers. In addition, upon detachment from the His-domain, the two nucleotide-binding sub domains undergo a ~40° hinge motion that opens the active site cleft. | The enzyme contains two remotely located reaction centers ~45 Å apart; the PEP/pyruvate partial reaction (step 1) takes place at the C-terminal domain (adopting an α/β barrel fold) and the nucleotide and inorganic phosphate partial reactions (steps 2 and 3) take place at the N-terminal domain (adopting the ATP grasp fold with two sub domains). A central domain, tethered to the N- and C-terminal domains by two closely-associated linkers, contains a phosphorylatable histidine residue (His455). To shuttle the phosphoryl group between the two reaction centers, the His-domain undergoes a ~110° swivel motion around the two linkers. In addition, upon detachment from the His-domain, the two nucleotide-binding sub domains undergo a ~40° hinge motion that opens the active site cleft. | ||