Prebiotic Membranes and Micelles Do Not Inhibit Peptide Formation During Dehydration

Cohen, Zachary R.; Kessenich, Brenda L; Hazra, Avijit; Nguyen, Julia; Johnson, Richard S.; MacCoss, Michael J.; Lalić, Gojko; Black, Roy A.; Keller, Sarah L.

doi:10.1002/cbic.202100614

Cited by 5 publications

(5 citation statements)

References 47 publications

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“…Moreover, the chirality of newly formed dipeptides could have been influenced by the vesicle-associated Leu-Leu. The chirality of dipeptides does influence the chirality of some other prebiotic molecules during their synthesis (e.g., pentoses formed from glyceraldehyde and glycoaldehyde), and peptides do form following drydown of amino acids in the presence of fatty acid vesicles . The first enzymes may then have consisted of peptides bound to a membrane, acting as unstructured proteins do today …”

Section: Resultsmentioning

confidence: 99%

“…The chirality of dipeptides does influence the chirality of some other prebiotic molecules during their synthesis (e.g., pentoses formed from glyceraldehyde and glycoaldehyde 43 ), and peptides do form following drydown of amino acids in the presence of fatty acid vesicles. 44 The first enzymes may then have consisted of peptides bound to a membrane, acting as unstructured proteins do today. 45 The extent to which vesicles bearing homochiral Leu-Leu could have been selected over those with heterochiral Leu-Leu depends on prebiotic conditions.…”

Section: Both Molecular Simulations and The Sequence Dependence Of Ef...mentioning

confidence: 99%

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Stabilization of Prebiotic Vesicles by Peptides Depends on Sequence and Chirality: A Mechanism for Selection of Protocell-Associated Peptides

Cohen,

Todd,

Maibaum

et al. 2024

Langmuir

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Cells require oligonucleotides and polypeptides with specific, homochiral sequences to perform essential functions, but it is unclear how such oligomers were selected from random sequences at the origin of life. Cells were probably preceded by simple compartments such as fatty acid vesicles, and oligomers that increased the stability, growth, or division of vesicles could have thereby increased in frequency. We therefore tested whether prebiotic peptides alter the stability or growth of vesicles composed of a prebiotic fatty acid. We find that three of 15 dipeptides tested reduce salt-induced flocculation of vesicles. All three contain leucine, and increasing their length increases the efficacy. Also, leucine–leucine but not alanine–alanine increases the size of vesicles grown by multiple additions of micelles. In a molecular simulation, leucine–leucine docks to the membrane, with the side chains inserted into the hydrophobic core of the bilayer, while alanine–alanine fails to dock. Finally, the heterochiral forms of leucine–leucine, at a high concentration, rapidly shrink the vesicles and make them leakier and less stable to high pH than the homochiral forms do. Thus, prebiotic peptide-membrane interactions influence the flocculation, growth, size, leakiness, and pH stability of prebiotic vesicles, with differential effects due to sequence, length, and chirality. These differences could lead to a population of vesicles enriched for peptides with beneficial sequence and chirality, beginning selection for the functional oligomers that underpin life.

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Section: Resultsmentioning

confidence: 99%

Section: Both Molecular Simulations and The Sequence Dependence Of Ef...mentioning

confidence: 99%

Stabilization of Prebiotic Vesicles by Peptides Depends on Sequence and Chirality: A Mechanism for Selection of Protocell-Associated Peptides

Cohen,

Todd,

Maibaum

et al. 2024

Langmuir

Self Cite

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“…In this case, we observed greatly increased transformation efficiency, with 78 ± 1.6% of the aerosol particles converting to vesicles ( Figures 2 C and S13 ). As a control, heptanoic acid, a lipid that does not form vesicles, 41 was sprayed into the same landing solution of 2:1 decanoic acid/decanol. Here, only 5.8 ± 2.1% of the aerosols transformed into vesicles.…”

Section: Resultsmentioning

confidence: 99%

Model Atmospheric Aerosols Convert to Vesicles upon Entry into Aqueous Solution

Nader

Baccouche

Connolly

et al. 2022

ACS Earth Space Chem.

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Aerosols are abundant on the Earth and likely played a role in prebiotic chemistry. Aerosol particles coagulate, divide, and sample a wide variety of conditions conducive to synthesis. While much work has centered on the generation of aerosols and their chemistry, little effort has been expended on their fate after settling. Here, using a laboratory model, we show that aqueous aerosols transform into cell-sized protocellular structures upon entry into aqueous solution containing lipid. Such processes provide for a heretofore unexplored pathway for the assembly of the building blocks of life from disparate geochemical regions within cell-like vesicles with a lipid bilayer in a manner that does not lead to dilution. The efficiency of aerosol to vesicle transformation is high with prebiotically plausible lipids, such as decanoic acid and decanol, that were previously shown to be capable of forming growing and dividing vesicles. The high transformation efficiency with 10-carbon lipids in landing solutions is consistent with the surface properties and dynamics of shortchain lipids. Similar processes may be operative today as fatty acids are common constituents of both contemporary aerosols and the sea. Our work highlights a new pathway that may have facilitated the emergence of the Earth's first cells.

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“…pentoses formed from glyceraldehyde and glycoaldehyde 32 ), and peptides form following drydown of amino acids in the presence of fatty acid vesicles. 33 The first enzymes may then have consisted of peptides bound to a membrane, acting as unstructured proteins do today. 34 A remaining question is how vesicles with more homo-than heterochiral Leu-Leu could have arisen to begin with.…”

Section: Heterochiral Leu-leu Reduces Vesicle Size and Increases Leak...mentioning

confidence: 99%

Stabilization of prebiotic vesicles by peptides depends on sequence and chirality

Black

Cohen

Todd

et al. 2023

Preprint

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Life depends on homochiral oligomers with specific sequences to carry out essential functions. How could such oligomers have been selected from the prebiotic clutter? What was the first function for which sequences were selected? Cells were probably preceded by simple compartments, such as fatty acid vesicles, composed of a membrane and one or more oligomers. Differential stabilization of such vesicles could have been the key to answering these questions. Oligomers that increased stability and/or growth of the membrane would have conferred an advantage to vesicles competing for limited membrane components. We therefore tested whether prebiotic peptides (simple oligomers) alter the stability or growth of vesicles composed of a prebiotic fatty acid. We find that one of the peptides, leucine-leucine (Leu-Leu), rapidly shrinks the vesicles and makes them leakier when heterochiral (either L-D or D-L), but not when homochiral (either L-L or D-D). Testing for effects on salt-induced flocculation of vesicles, we find three of fifteen dipeptides reduce flocculation. All three contain leucine, and increasing length increases efficacy. In a final test for modulation of vesicle properties, we find two leucine-containing peptides that increase the size of fatty acid vesicles grown by multiple additions of fatty acid micelles, and a tripeptide outperforms a dipeptide. Thus, prebiotic peptides influence the size, leakiness, susceptibility to flocculation, and growth of prebiotic vesicles and do so with specificity for chirality, sequence, and length. Vesicles that bound peptides favoring stability and/or growth could have outcompeted other vesicles for lipid components of the membrane, beginning selection for the functional oligomers that underpin life.

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Prebiotic Membranes and Micelles Do Not Inhibit Peptide Formation During Dehydration

Cited by 5 publications

References 47 publications

Stabilization of Prebiotic Vesicles by Peptides Depends on Sequence and Chirality: A Mechanism for Selection of Protocell-Associated Peptides

Stabilization of Prebiotic Vesicles by Peptides Depends on Sequence and Chirality: A Mechanism for Selection of Protocell-Associated Peptides

Model Atmospheric Aerosols Convert to Vesicles upon Entry into Aqueous Solution

Stabilization of prebiotic vesicles by peptides depends on sequence and chirality

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