Enzymes from piezophiles

Abstract

The discovery of microbial communities in extreme conditions that would seem hostile to life leads to the question of how the molecules making up these microbes can maintain their structure and function. While microbes that live under extremes of temperature have been heavily studied, those that live under extremes of pressure, or "piezophiles", are now increasingly being studied because of advances in sample collection and high-pressure cells for biochemical and biophysical measurements. Here, adaptations of enzymes in piezophiles against the effects of pressure are discussed in light of recent experimental and computational studies. However, while concepts from studies of enzymes from temperature extremophiles can provide frameworks for understanding adaptations by piezophile enzymes, the effects of temperature and pressure on proteins differ in significant ways. Thus, the state of the knowledge of adaptation in piezophile enzymes is still in its infancy and many more experiments and computational studies on different enzymes from a variety of piezophiles are needed.

Properties and Applications of Extremozymes from Deep-Sea Extremophilic Microorganisms: A Mini Review

“…Consequently, the ability to live under extreme pressures requires substantial physiological adaptations that involve modifications to gene regulation and the cellular structure. The adaptative mechanisms of piezophiles have not yet been fully clarified but are known to involve a reduction in cell division, the production of compatible osmolytes and polyunsaturated fatty acids, a switch in the flexibility state, and the formation of multimeric and antioxidant proteins [118][119][120][121]. Lauro et al have also described the occurrence of extended helices in the 16S ribosomal RNA (rRNA) genes for adaptation to high pressures [122].…”

“…So far, very little research has been conducted on deep-sea piezophilic enzymes [117,123], and many more experiments and computational studies on different enzymes from a variety of piezophiles are required to advance our understanding [120]. However, piezophilic proteins have shown high efficiency in several industrial processes [5], with particular applications for food production, where high pressures are employed for the processing and sterilisation of food materials [124].…”

High-pressure adaptation of extremophiles and biotechnological applications

“…The protein adaptation to extreme conditions is a balance between the imperative stability (higher number of bounds) to be functional and the flexibility (lower number of bounds) to be capable to adapt to different conditions [103]. One of the most studied Proteins from piezophiles may have a larger total volume of small internal cavities, which makes the protein more compressible and less sensitive to distortion caused by pressure [105]. Moreover, the presence of small cavities allows water penetration at HP and consequently increases the hydration but, as seen in MpDHFR, cavities are not big enough to cause the protein denaturation but allow the protein to be more flexible.…”

“…MpDHFR seems to have higher sensitivity to pressure due to its higher flexibility[104]. A more flexible protein may explain the higher absolute activity of piezophile proteins[105].However, most of studies are done in protein-isolated solutions, which differs from their native state. An innovative quasi-elastic neutron scattering study examined the dynamics from whole cells of the piezophile Thermococcus barophilus and the piezosensitive Thermococcus kodakarensis microorganism under atmospheric pressure and 40 MPa.…”

Adaptation of Saccharomyces cerevisiae to high pressure (15, 25 and 35 MPa) to enhance the production of bioethanol

“…However, in some cases, these microorganisms are able to grow under these stress conditions, due to the development of mechanisms to improve pressure resistance. Some of these mechanisms are very similar to those used by piezophiles (organisms whose survival and reproduction are optimized to high pressures (Ichiye, 2018)), but with lower efficiency (Oger & Jebbar, 2010). High pressure can exert a broad range of effects on microorganisms with similar characteristics to those of other environmental stresses, such as high temperature, ethanol and oxidative stresses.…”