Glacier ice worms, such as Mesenchytraeus solifugus, are the only known macroscopic organisms that reside permanently in ice, and they exhibit an unusual bioenergetic profile where intracellular ATP levels increase with declining temperature, which is the opposite of what is observed in other organisms. Eric Klein’s lab at Rutgers found compelling evidence that a unique histidine-rich C-terminal extension on the ice worm mitochondrial ATP6, a subunit of the ATP synthase, can significantly enhance ATP synthesis activity when transferred to bacteria. The unique C-terminal extension increases the efficiency of ATP synthesis by about 5-fold when transferred to the E. coli ATP6 homolog. This increased ATP synthesis appears to be unidirectional, as there was no change in the ATP hydrolysis rate. The C-terminal extension of the ATP6 subunit likely increases the activity of the ATP synthase enzyme in bacteria by facilitating proton translocation through the enzyme's pore. This discovery sheds light on a potential adaptation mechanism in a psychrophilic organism and opens new avenues for understanding and potentially manipulating ATP production in various biological systems. Further research is needed to fully elucidate the mechanism of action of this extension and its specific role in the cold adaptation of ice worms.
Dunkley T, Shain DH, Klein EA. A histidine-rich extension of the mitochondrial F0 subunit ATP6 from the ice worm Mesenchytraeus solifugus increases ATP synthase activity in bacteria. FEBS Lett. 2025 Jan 17. doi: 10.1002/1873-3468.15100. Epub ahead of print. PMID: 39821116. https://febs.onlinelibrary.wiley.com/doi/10.1002/1873-3468.15100
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