Abstract EANA2025-111

Unlike other organisms, hyperthermophiles are unique microorganisms thriving under high temperatures. To grow under these conditions, the biomolecules in hyperthermophiles must remain stable and interact adequately at high temperature. The relationship of temperature to the structure of macromolecules (i.e., proteins, nucleic acids, lipids) has been studied for years (1, 2). Nevertheless, there are some additional key aspects that remain to be deciphered to fully understand how hyperthermophilic cells are able to live at high temperatures (near or above 100ºC). Three points will be discussed: the stability of small biomolecules highly sensible to temperature (e.g., NADH, ATP, pyridoxal phosphate)(3), the relevance of the dimensions of molecular channels in the enzymes from hyperthermophiles (4) and the importance of maintaining the interactions between proteins and other biomolecules under those conditions. At the highest temperatures for life, and according to physical principles, there should be excessive molecular mobility and kinetic energy seriously affecting biomolecule stability and structure as well as compromising the interactions between biomolecules required to maintain functionality within the cells. Small biomolecules can gain stability by maintaining intracellular viscosity. The dimensions of molecular channels in the enzymes of hyperthermophiles become increasingly restricted at high temperatures. The maintenance of cellular interactions between proteins and other biomolecules are an essential and functional feature for cells to thrive at high temperature. Besides the structure of macromolecules, small biomolecule stability, molecular channels and biomolecule interactions are critical aspects to consider to be able to explain the possibility of life around the boiling point of water.

References

1. Cowan, D.A. 2004. The upper temperature of life – where do we draw the line? Trends Microbiol. 12: 58-60.

2. Vieille, C., G.J. Zeikus. 2001. Hyperthermophilic enzymes: sources, uses, and molecular mechanisms for thermostability. Microbiol. Mol. Biol. Rev. 65: 1-43.

3. Cuecas, A., J. Cruces, J.F. Galisteo-López, X. Peng, J.M. Gonzalez. 2016. Cellular viscosity in prokaryotes and thermal stability of low molecular weight biomolecules. Biophys. J. 111: 875-882.

4. Ginsbach, L.F., J.M. Gonzalez. 2022. Understanding life at high temperatures: relationships of molecular channels in enzymes of methanogenic Archaea and their growth temperatures. Int. J. Mol. Sci. 23: 15149.