Limits...
Membrane alternatives in worlds without oxygen: Creation of an azotosome.

Stevenson J, Lunine J, Clancy P - Sci Adv (2015)

Bottom Line: The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water.Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature.As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Biomolecular Engineering, Cornell University, 365 Olin Hall, Ithaca, NY 14853, USA.

ABSTRACT
The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water. This fact has caused astronomers who seek conditions suitable for life to search for exoplanets within the "habitable zone," the narrow band in which liquid water can exist. However, can cell membranes be created and function at temperatures far below those at which water is a liquid? We take a step toward answering this question by proposing a new type of membrane, composed of small organic nitrogen compounds, that is capable of forming and functioning in liquid methane at cryogenic temperatures. Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature. As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface.

No MeSH data available.


Related in: MedlinePlus

Potential energy profile for the decomposition of acrylonitrile.The largest instantaneous energy barrier is the activation energy to decompose the azotosome.
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Figure 7: Potential energy profile for the decomposition of acrylonitrile.The largest instantaneous energy barrier is the activation energy to decompose the azotosome.

Mentions: The potential energy barrier for each azotosome was calculated by finding the largest single uninterrupted increase in the potential energy during the decomposition of each azotosome. The concept of a rate-determining, Arrhenius-style energy barrier relies on the barrier being uninterrupted. If there is a stable intermediate state at which the system can reequilibrate, then it is not one barrier, but two smaller barriers, with a drastic increase in the implied rate of reaction. Because we used umbrella sampling, with its fine-grained view of the energy profiles, we were able to divide them into very fine sections (0.05 Å) and make sure that there were no intermediate states within our barriers. An example barrier (acrylonitrile) is shown in Fig. 7.


Membrane alternatives in worlds without oxygen: Creation of an azotosome.

Stevenson J, Lunine J, Clancy P - Sci Adv (2015)

Potential energy profile for the decomposition of acrylonitrile.The largest instantaneous energy barrier is the activation energy to decompose the azotosome.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644080&req=5

Figure 7: Potential energy profile for the decomposition of acrylonitrile.The largest instantaneous energy barrier is the activation energy to decompose the azotosome.
Mentions: The potential energy barrier for each azotosome was calculated by finding the largest single uninterrupted increase in the potential energy during the decomposition of each azotosome. The concept of a rate-determining, Arrhenius-style energy barrier relies on the barrier being uninterrupted. If there is a stable intermediate state at which the system can reequilibrate, then it is not one barrier, but two smaller barriers, with a drastic increase in the implied rate of reaction. Because we used umbrella sampling, with its fine-grained view of the energy profiles, we were able to divide them into very fine sections (0.05 Å) and make sure that there were no intermediate states within our barriers. An example barrier (acrylonitrile) is shown in Fig. 7.

Bottom Line: The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water.Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature.As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical and Biomolecular Engineering, Cornell University, 365 Olin Hall, Ithaca, NY 14853, USA.

ABSTRACT
The lipid bilayer membrane, which is the foundation of life on Earth, is not viable outside of biology based on liquid water. This fact has caused astronomers who seek conditions suitable for life to search for exoplanets within the "habitable zone," the narrow band in which liquid water can exist. However, can cell membranes be created and function at temperatures far below those at which water is a liquid? We take a step toward answering this question by proposing a new type of membrane, composed of small organic nitrogen compounds, that is capable of forming and functioning in liquid methane at cryogenic temperatures. Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature. As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface.

No MeSH data available.


Related in: MedlinePlus