Life has been found in many extremes of pressure P, temperature T, and chemical composition X. There are speculations that life on Earth may have originated in deep-sea hydrothermal vents at high P and T and that life on Mars may exist deep subsurface, also at high P and T. This leads to the question of how proteins necessary for life can function at extreme P-T-X. Our focus is mainly on extremes of pressure. First, molecular dynamics simulations of the enzyme dihydrofolate reductase (DHFR) show how P and T affect proteins and how a protein from a piezophile (pressure-loving) is adapted relative to the homologous protein from a mesophile (moderate-loving). Next, molecular dynamics simulations of [4Fe-4S] ferredoxin show how early proteins may have utilized salts in the environment to extend functional control beyond their amino acid sequence, and how P could affect this.
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Toshiko Ichiye (Georgetown University)