The Effects of Temperature and Pressure on Protein-Ligand Binding in the Presence of Mars-Relevant Salts

Abstract

Protein–ligand interactions are fundamental to all biochemical processes. Generally, these processes are studied at ambient temperature and pressure conditions. We investigated the binding of the small ligand 8-anilinonaphthalene-1-sulfonic acid (ANS) to the multifunctional protein bovine serum albumin (BSA) at ambient and low temperatures and at high pressure conditions, in the presence of ions associated with the surface and subsurface of Mars, including the chaotropic perchlorate ion. We found that salts such as magnesium chloride and sulfate only slightly affect the protein–ligand complex formation. In contrast, magnesium perchlorate strongly affects the interaction between ANS and BSA at the single site level, leading to a change in stoichiometry and strength of ligand binding. Interestingly, both a decrease in temperature and an increase in pressure favor the ligand binding process, resulting in a negative change in protein–ligand binding volume. This suggests that biochemical reactions that are fundamental for the regulation of biological processes are theoretically possible outside standard temperature and pressure conditions, such as in the harsh conditions of the Martian subsurface.

Ions in the Deep Subsurface of Earth, Mars, and Icy Moons: Their Effects in Combination with Temperature and Pressure on tRNA–Ligand Binding

“…Conversely, a drastic decrease of K b was observed in the presence of the MgSO 4 , reaching a value of K b = 0.009 × 10 6 M −1 , which can be due to the binding of sulfate to ThT, thereby hampering the interaction with tRNA (see the Discussion section). Collectively, these data highlight the ability of Mg salts to strongly modulate the complex formation between ThT and tRNA, which is a phenomenon that has been previously observed also for protein–ligand interactions [ 42 ].…”

Deep sea osmolytes in action: their effect on protein–ligand binding under high pressure stress

“…Pressure modulation allowed us to decipher the volumetric properties of the complex formation in terms of packing (including fluctuations) and hydration changes and the effects of cosolvents on them. 64,65 Under pure buffer conditions, a biphasic pressure dependence of ln K b was observed, Δ V b for both proteins is positive in the low-pressure range and becomes negative at higher pressures (above about 1400 bar). Such behavior could originate from structural fluctuations of the protein–ligand complex in the lower pressure-regime, which would contribute positively to the volume change ( i.e.…”

Effect of Tetraphenylborate on Physicochemical Properties of Bovine Serum Albumin

“…These phenomena can be invoked by variations in the temperature and/or the pH of a solution. Consequently, the environmental conditions may affect the binding properties of a biomolecule, such as the affinity of low-molecular weight compounds to a protein, the number of potential binding sites, and the stoichiometry of the resulting protein-ligand complexes [7]. As a result, the biological and pharmacological activity of the protein is often highly influenced by the presence of the different ligands in the system.…”