Cyanamide mediated synthesis under plausible primitive earth conditions

Epps, Dennis E. Van; Nooner, D. W.; Eichberg, Joseph; Sherwood, E.; Oró, J.

doi:10.1007/bf01732490

Cited by 34 publications

(29 citation statements)

References 9 publications

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“…Because the off-rate of a lipid from a bilayer is dependent on the number of carbon atoms in its acyl chain(s), a very long chain monoacyl lipid that remains in the bilayer indefinitely would be sufficient to drive growth. However, there is no prebiotic route to such species, whereas diacyl lipid synthesis is a simple chemical means of producing insoluble lipids via the linkage of two, short acyl chains (20,21).…”

Section: Resultsmentioning

confidence: 99%

Physical effects underlying the transition from primitive to modern cell membranes

Budin

Szostak

2011

Proc. Natl. Acad. Sci. U.S.A.

237

270

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To understand the emergence of Darwinian evolution, it is necessary to identify physical mechanisms that enabled primitive cells to compete with one another. Whereas all modern cell membranes are composed primarily of diacyl or dialkyl glycerol phospholipids, the first cell membranes are thought to have self-assembled from simple, single-chain lipids synthesized in the environment. We asked what selective advantage could have driven the transition from primitive to modern membranes, especially during early stages characterized by low levels of membrane phospholipid. Here we demonstrate that surprisingly low levels of phospholipids can drive protocell membrane growth during competition for single-chain lipids. Growth results from the decreasing fatty acid efflux from membranes with increasing phospholipid content. The ability to synthesize phospholipids from single-chain substrates would have therefore been highly advantageous for early cells competing for a limited supply of lipids. We show that the resulting increase in membrane phospholipid content would have led to a cascade of new selective pressures for the evolution of metabolic and transport machinery to overcome the reduced membrane permeability of diacyl lipid membranes. The evolution of phospholipid membranes could thus have been a deterministic outcome of intrinsic physical processes and a key driving force for early cellular evolution.origin of life | ribozymes | coevolution T he first cell membranes are likely to have formed from simple, single-chain lipids such as short-chain fatty acids and their derivatives that were present in the prebiotic environment (1, 2). Membranes composed of such amphiphiles are permeable to polar nutrients such as nucleotides (3) and feature the dynamic properties necessary for spontaneous growth and division (2, 4). The high permeability of fatty-acid-based membranes is consistent with a heterotrophic model for early cells, in which chemical building blocks are synthesized in the environment and passively diffuse across the cell membrane to participate in replication. All modern cells synthesize phospholipids (or sulfolipids in rare exceptions; refs. 5 and 6) with two hydrophobic chains as their primary membrane lipids. Phospholipid membranes prevent the rapid permeation of ions and polar molecules, allowing modern cells to retain internally synthesized metabolites and to control all import and export. The evolution of phospholipid membranes must have therefore mirrored the emergence of metabolic and transport machinery during early cellular evolution.This transition from single-chain lipids to phospholipids had to be gradual, both to allow for the coevolution of metabolic and transport machinery and because of the initial inefficiency of nascent catalysts (e.g., ribozymes). Hence, the selective advantage associated with phospholipid synthesis had to apply to small differences in phospholipid content in order to drive this transition. What selective advantage could be conferred by the low levels of phospholipid that mus...

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Section: Resultsmentioning

confidence: 99%

Physical effects underlying the transition from primitive to modern cell membranes

Budin

Szostak

2011

Proc. Natl. Acad. Sci. U.S.A.

237

270

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“…Biological phosphate esters such as glycerol phosphates and phosphoethanolamine enjoy a special place in the biochemistry of living organisms. Prebiotic synthesis of glycerol phosphates has been demonstrated earlier, which, so far, is the only remarkable prebiotic synthesis of glycerol phosphates [25]. In addition, there are no efficient methods described to synthesize the phosphate esters under prebiotic conditions [26].…”

Section: Introductionmentioning

confidence: 97%

Resolving the enigma of prebiotic COP bond formation: Prebiotic hydrothermal synthesis of important biological phosphate esters

Gull

Wang

et al. 2010

Heteroatom Chemistry

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Important biological phosphate esters such as sn-glycerol-3-phosphate, glycerol-2-phosphate, and phosphoethanolamine were synthesized under hydrothermal conditions. Phosphorus was incorporated into the biomolecules, leading to the formation of C O P type compounds hydrothermally. Only perlite-catalyzed reaction at 180• C could result in the formation of sn-glycerol-3-phosphate, whereas glycerol-2-phosphate could be easily synthesized at 100• C with or without minerals and phosphoethanolamine was obtained within a temperature range of 100 to 120

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“…Phospholipids can form abiotically when fatty acids, glycerin, and phosphate are moderately heated (65°C) to dryness. While complex phospholipids can be synthesized under hypothetical early-Earth conditions (Hargreaves et al 1977;Hargreaves and Deamer 1978;Eichberg et al 1977;Epps et al 1978Epps et al , 1979Rao et al 1982Rao et al , 1987, have pointed out that the simultaneous presence of fatty acids, glycerol, and phosphate on the early Earth is highly unlikely. The relevance of a reaction requiring complete dehydration under early-Earth conditions is also questionable.…”

Section: Cell Membranesmentioning

confidence: 97%

The Influence of Environmental Conditions, Lipid Composition, and Phase Behavior on the Origin of Cell Membranes

Thomas

Rana²

2007

Orig Life Evol Biosph

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At some point in life's development, membranes formed, providing barriers between the environment and the interior of the 'cell.' This paper evaluates the research to date on the prebiotic origin of cell membranes and highlights possible areas of continuing study. A careful review of the literature uncovered unexpected factors that influence membrane evolution. The major stages in primitive membrane formation and the transition to contemporary cell membranes appear to require an exacting relationship between environmental conditions and amphiphile composition and phase behavior. Also, environmental and compositional requirements for individual stages are in some instances incompatible with one another, potentially stultifying the pathway to contemporary membranes. Previous studies in membrane evolution have noted the effects composition and environment have on membrane formation but the crucial dependence and interdependence on these two factors has not been emphasized. This review makes clear the need to focus future investigations away from proof-of-principle studies towards developing a better understanding of the roles that environmental factors and lipid composition and polymorphic phase behavior played in the origin and evolution of cell membranes.

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Cyanamide mediated synthesis under plausible primitive earth conditions

Cited by 34 publications

References 9 publications

Physical effects underlying the transition from primitive to modern cell membranes

Physical effects underlying the transition from primitive to modern cell membranes

Resolving the enigma of prebiotic COP bond formation: Prebiotic hydrothermal synthesis of important biological phosphate esters

The Influence of Environmental Conditions, Lipid Composition, and Phase Behavior on the Origin of Cell Membranes

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