Extremophiles Features And Role

Table of Contents

Significance for Extremophiles

Role Proteins Play in Extremophiles

Extreme cold – Psychrophiles

Extreme heat-Thermophiles

Salt-loving – Halophilic

Organisms that are capable of surviving and thriving in extremely harsh environments.

Extremophiles refer to organisms that can live in extreme conditions. These conditions were believed not to be able to support life.

Three domains exist in life: Eukarya and Bacteria. Each domain is unique and has its own features. The Archaean domain hosts the most prominent extremophiles. Even though penguins are classified as extremophiles, most known extremophiles are micro-organisms; the main types of extremophiles that scientists study are from the Archaea and Bacteria domain of life.Significance of ExtremophilesStudying extremophiles can offer us a solid grasp of the physiochemical limitations defining life on our planet. It is possible that primitive Earth environments had high levels of extreme heat. Extremophiles may be a remnant of ancient organisms that could help us understand how life evolved on Earth.

Role of Proteins in ExtremophilesExtremophiles owe most of their ability to be able to sustain themselves in such harsh conditions to proteins. Protein folding is an integral part of survival in any living organism. RNA Translation is essential in the making of proteins. Organisms wouldn’t be able to function without it. There are many adaptions available that will work in all environments. Archaea, however, have developed distinct protein functions to adapt to specific environments. Understanding how proteins adapt to extreme environments allows organisms to survive is key to understanding the limits of life on Earth and in other parts of our Solar System.

Extreme cold – PsychrophilesOne kind of extremophile is the Psychrophiles. These organisms can survive at extremely low temperatures. These organisms can survive in extremely cold environments such as deep seas, permafrosts, glaciers and snowfields. At 2degC, deep ocean water is quite stable. However, the water can reach temperatures down to -12degC thanks to its high salt content. It has been proven that soils below -39degC have microbial activity.

Studies have shown that Psychrophiles possess a variety of features that enable them to perform cold-temperature protein folding and gene translation.

Normal conditions show that proteins, specifically enzymes, lose activity when temperatures fall below 20°C. This is bad news for cells that need to grow. Low temperatures lead to decreased enzyme activity. This is because cells have low kinetic energy. Low kinetic energie means conformational movements are slower and thus less efficient.

Because psychrophilic proteins have greater flexibility, they can be moved and changed conformation more easily. This allows psychrophilic proteins to maintain high activity at low temperatures. A psychrophilic enzyme typically has 10 times the activity of a normal temperature mesophilic enzyme.

Extreme heat -ThermophilesThermophiles are able to grow between 50degC and 70degC, while hyperthermophiles can grow optimally up to 105degC, with a limit of 110 degC to 121 degC. These organisms are found in marine and terrestrial geothermally-heated habitats such as sediment of volcanic islands, hydrothermal systems, shallow terrestrial hotsprings, deep sea hydrothermal outlets, and sediment of volcanic island.

Every cell has an outer membrane which regulates what enters and exits the cell. The cell’s outer membrane protects its inner contents from damage by the environment. The cell membrane’s most important component is the lipid bilayer. This provides protection to the membrane. Lipids are fats and are not soluble in water. The bilayer contains phospholipids, which are the most common type of lipid molecules.

In extreme heat, cell membranes “normal” organisms can become more flexible. Cell lysing occurs when the membrane becomes too flexible. The cell is unable to protect itself from the damage and will eventually die. Extreme heat can cause irreversible unfolding of “normal” proteins, which exposes hydroponics centers, leading to aggregation. Proteins that form aggregates will stop functioning properly.

The phospholipids are modified slightly in thermophiles. The fatty oils of phospholipids tend to be longer, have more side chain, and are saturated. The thermostability is promoted by the large number of large hydrophobic and disulphide bonds, as well as ionic interactions. A better backing of thermophiles would stop water molecules from entering the protein core and destabilizing it. Water destabilizes proteins because of its efficiency at hydrogen bonding with macromolecules. This rigid membrane makes it stable in hot environments.

The thermophile forms heat shock proteins to prevent aggregate formation and denaturation. These proteins can form heat shock proteins, which can help prevent aggregates from forming.

Extra salty – HalophilicHalophiles love salt and thrive in salty environments. They can be found in hypersaline environments in a variety of locations across the globe, including underground salt mines as well as deep-sea and coastal locations. There are many places where halophilic organisms are found, such as the Dead Sea or Great Salt Lake. The ability of sodium chloride to alter the conformation and stability of a protein can result in a decrease in its functionality.

Some halophilic bacterias, eukaryotes and other organisms are capable of preventing salts from entering their cells.

However, Halophilic Archaea consume high levels of salts. A non-halophilic organism will have higher salt concentrations, so water tends to surround its ionic lattice. Non-halophilic organisms have less water. Hydrophobic amino acid in non-halophilic proteins lose their hydration and aggregate due to a reduced water readiness. This alters the structure of non-halophilic protein, causing the organism to be unstable.

Inorganic salt is a high-concentration of inorganic salt that allows proteins from halophilic Archaea to stabilise the native protein fold. A large number of acid residues are found on halophilic proteins. These acid residues could play two roles. The first is to ensure that the protein remains in solution. Acid residues can make the protein’s surface more negatively charged. The negative charge will attract water molecules to it, which allows the protein to compete against other ions for those molecules. Additionally, acid residues can bind to hydrated cation which can keep the protein hydrated.

PolyextremophilesSome extremophiles are adapted simultaneously to multiple stresses (polyextremophile); common examples include thermoacidophiles and haloalkaliphiles. These organisms can tolerate extreme environmental conditions.