Pressure‐Tuning the Conformation of Bovine Pancreatic Trypsin Inhibitor Studied by Fourier‐Transform Infrared Spectroscopy

Abstract

A hydrostatic pressure of 1 .5 GPa induces changes in the secondary structure of bovine pancreatic tryspin inhibitor (BPTI) as revealed by the analysis of the amide I' band with Fourier-transform infrared (FTIR) spectroscopy in the diamond anvil cell. The features of the secondary structure remain distinct at high pressure suggesting that the protein does not unfold. The fitted percentages of the secondary structure elements during compression and decompression strongly suggest that the pressure-induced changes are reversible. The pressure-induced changes in the tyrosine side chain band are also reversible. The results demonstrate that the infrared technique explores different aspects of the behaviour of proteins in comparison with two published molecular dynamics studies performed up to 1

Molecular Dynamics Simulations To Determine the Effect of Supercritical Carbon Dioxide on the Structural Integrity of Hen Egg White Lysozyme

“…Subsequent MD simulations revealed that changes in the secondary structures between 10 and 15 kbar were observed (60). These changes could be correlated with changes in the secondary structure observed with high-pressure infrared studies (61). Furthermore, no net unfolding of lysozyme was observed at 10 kbar after 210 ps (20).…”

Biology under extreme conditions

“…The data that bacterial life may still be possible at pressure above 1 GPa [7] came therefore as a surprise. Only very few proteins have been found to be resistant to such high pressures [20][21][22].…”

“…However, since proteins are usually studied at low molar concentrations, the role of the solvent is often underestimated. Several reports indicate the crucial role of water in protein unfolding [20,30].…”

“…Secondly, when the fibres are formed in H 2 O and then transferred to D 2 O, a subsequent compression up to more than 1 GPa does not induce an extensive exchange of H for D. This indicates that the core of the fibrils is extremely resistant to pressure, a phenomenon that is only observed in very limited number of proteins [20][21][22]. Further studies are in progress to see whether this is a general property of fibrils formed from a wide variety of proteins.…”

Evidence of a Structural Defect in Ice VII and the Side-Chain-Dependent Response of Small Model Peptides to Increased Pressure

“…While the majority of proteins irreversibly denature at pressures of a few kbar, there are numerous examples of proteins that maintain their structures at well over 10 kbar of pressure. 3–4 Likewise, barophilic organisms have been collected in even the deepest parts of the ocean and below the ocean floor, and many microbes are capable of surviving and growing at pressures of over 10 kbar. 5 As more research is done on deep sea environments it is becoming clear that barophilic organisms may be the rule rather than the exception, and that life may exist and even thrive far below even the deepest parts of the ocean.…”