As the LKB1 → AMPK signalling pathway is activated by elevation of the AMP/ATP ratio, it is switched on by any metabolic stress that disturbs energy balance by interfering with ATP synthesis ...

Proton motive force: The electrochemical gradient across a membrane, generated by differences in proton concentration, that powers ATP synthesis. Energy Transduction and ATP Synthesis Mechanisms ...

In every synthesis reported in standard text books, they USE ATP itself to carry out the cyclization. Here is where I find it funny. Because YOU CAN NOT USE ATP to make ATP- it is as simple as that.