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Natural molecules to protect membranes against dehydration. Osmolytes and dehydrin proteins.

Mateos, Helena LU (2016) KEMR17 20161
Department of Chemistry
Abstract
In this study, we have investigated some mechanisms used in nature to protect membranes and other self-assembled biomolecular structures against changes in hydration. One common mechanism used by many living organisms is the accumulation of small polar solutes with low vapor pressure that stabilize the cell membranes in cases of osmotic stress.1 These molecules are known as osmolytes. Among other mechanisms, plants also synthesize dehydrin proteins, which are found in vegetative tissues, and that are believed to protect membranes from conditions like desiccation or cold stress.2 To elucidate the molecular mechanism of dehydrins, the effect of Lti30 protein on the swelling of a lipid lamellar system was studied by adding different water... (More)
In this study, we have investigated some mechanisms used in nature to protect membranes and other self-assembled biomolecular structures against changes in hydration. One common mechanism used by many living organisms is the accumulation of small polar solutes with low vapor pressure that stabilize the cell membranes in cases of osmotic stress.1 These molecules are known as osmolytes. Among other mechanisms, plants also synthesize dehydrin proteins, which are found in vegetative tissues, and that are believed to protect membranes from conditions like desiccation or cold stress.2 To elucidate the molecular mechanism of dehydrins, the effect of Lti30 protein on the swelling of a lipid lamellar system was studied by adding different water contents to samples with and without the protein present. On the other hand, the effect that Lti30 and two osmolytes, urea and trimethylamine N-oxide (TMAO), have on the phase transition of a lipid model system under dehydration conditions was studied by exposing the lipid systems to water at different relative humidities. Our results show that Lti30 interacts with the lipid membranes preventing them from swelling at high water contents. In the case of the lipid model system under dehydration conditions, Lti30 does not have any effect in the phase transition of the lipids but it increases the swelling of the phases. Urea has the effect of stabilizing the fluid lipid bilayers at low water activities, where otherwise a phase transition to a solid state would occur. Moreover, the swelling of the fluid lipid bilayers increases significantly in the presence of urea. Adding TMAO to the lipid model system has the effect of stabilizing the reverse structures by shifting the phase transition to higher water contents. (Less)
Popular Abstract
Nature has many mechanisms to protect living organisms from dehydration. Two of these mechanisms that are present in plants, are the accumulation of osmolytes, and the production of dehydrin proteins. Osmolytes are small substances that help balancing the volume of a cell, maintaining a good humidity.1 Proteins are large, complex molecules that have many different roles in living organisms. They are required for the function, regulation and structure of the body’s organs and tissues.2 Both osmolytes and dehydrins are believed to protect cell membranes against dehydration.
The cells of all living beings are confined and compartmentalized by membranes. The structural bases of cell membranes are lipid molecules, which are composed of two... (More)
Nature has many mechanisms to protect living organisms from dehydration. Two of these mechanisms that are present in plants, are the accumulation of osmolytes, and the production of dehydrin proteins. Osmolytes are small substances that help balancing the volume of a cell, maintaining a good humidity.1 Proteins are large, complex molecules that have many different roles in living organisms. They are required for the function, regulation and structure of the body’s organs and tissues.2 Both osmolytes and dehydrins are believed to protect cell membranes against dehydration.
The cells of all living beings are confined and compartmentalized by membranes. The structural bases of cell membranes are lipid molecules, which are composed of two parts, one that likes to be in contact with water, and one that does not. Due to the nature of some lipids they can form closed structures that separate inner and outer aqueous spaces.2
However, little is known about the molecular mechanism either osmolytes or dehydrin proteins. In the present study, the mechanism of a specific dehydrin, named Lti30, and two osmolytes, urea and trimethylamine N-oxide (TMAO), is investigated by preparing lipid model systems with different rates of hydration in the presence or absence of these molecules. Our results show that Lti30 interacts with the lipid membranes preventing them from swelling at high water contents. However, when subjecting the system to dehydration conditions, Lti30 does not show any effect in protecting lipid membranes from injuries. On the other hand, urea shows a stabilizing effect of the lipid bilayers at dehydration conditions while TMAO shows the opposite effect, destabilizing the lipid membranes under study. (Less)
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author
Mateos, Helena LU
supervisor
organization
course
KEMR17 20161
year
type
H2 - Master's Degree (Two Years)
subject
keywords
Phospholipids, Osmotic Pressure, Osmosis, Magnetic Resonance Spectroscopy, Proteins, physical chemistry, Cell Membrane, Dehydrin, Urea: chemistry, X-Ray Diffraction, fysikalisk kemi
language
English
id
8887712
date added to LUP
2016-08-30 11:12:10
date last changed
2016-08-30 11:12:10
@misc{8887712,
  abstract     = {In this study, we have investigated some mechanisms used in nature to protect membranes and other self-assembled biomolecular structures against changes in hydration. One common mechanism used by many living organisms is the accumulation of small polar solutes with low vapor pressure that stabilize the cell membranes in cases of osmotic stress.1 These molecules are known as osmolytes. Among other mechanisms, plants also synthesize dehydrin proteins, which are found in vegetative tissues, and that are believed to protect membranes from conditions like desiccation or cold stress.2 To elucidate the molecular mechanism of dehydrins, the effect of Lti30 protein on the swelling of a lipid lamellar system was studied by adding different water contents to samples with and without the protein present. On the other hand, the effect that Lti30 and two osmolytes, urea and trimethylamine N-oxide (TMAO), have on the phase transition of a lipid model system under dehydration conditions was studied by exposing the lipid systems to water at different relative humidities. Our results show that Lti30 interacts with the lipid membranes preventing them from swelling at high water contents. In the case of the lipid model system under dehydration conditions, Lti30 does not have any effect in the phase transition of the lipids but it increases the swelling of the phases. Urea has the effect of stabilizing the fluid lipid bilayers at low water activities, where otherwise a phase transition to a solid state would occur. Moreover, the swelling of the fluid lipid bilayers increases significantly in the presence of urea. Adding TMAO to the lipid model system has the effect of stabilizing the reverse structures by shifting the phase transition to higher water contents.},
  author       = {Mateos, Helena},
  keyword      = {Phospholipids,Osmotic Pressure,Osmosis,Magnetic Resonance Spectroscopy,Proteins,physical chemistry,Cell Membrane,Dehydrin,Urea: chemistry,X-Ray Diffraction,fysikalisk kemi},
  language     = {eng},
  note         = {Student Paper},
  title        = {Natural molecules to protect membranes against dehydration. Osmolytes and dehydrin proteins.},
  year         = {2016},
}