ATP-Assisted Protocellular Membrane Formation with Ethanolamine-Based Amphiphiles

Abstract

Prebiotic membranes are one of the essential elements of the origin of life because they build compartments to keep genetic materials and metabolic machinery safe. Since modern cell membranes are made up of ethanolamine-based phospholipids, prebiotic membrane formation with ethanolamine-based amphiphiles and phosphates might act as a bridge between the prebiotic and contemporary eras. Here, we report the prebiotic synthesis of O-lauroyl ethanolamine (OLEA), O-lauroyl methyl ethanolamine (OLMEA), and O-lauroyl dimethylethanolamine (OLDMEA) under wet–dry cycles. Turbidimetric, NMR, DLS, fluorescence, microscopy, and glucose encapsulation studies highlighted that OLEA-ATP and OLMEA-ATP form protocellular membranes in a 3:1 ratio, where ATP acts as a template. OLDMEA with a dimethyl group did not form any membrane in the presence of ATP. ADP can also template OLEA to form vesicles in a 2:1 ratio, but the ADP-templated vesicles were smaller. This suggests the critical role of the phosphate backbone in controlling the curvature of supramolecular assembly. The mechanisms of hierarchical assembly and transient dissipative assembly are discussed based on templated-complex formation via electrostatic, hydrophobic, and H-bonding interactions. Our results suggest that N-methylethanolamine-based amphiphiles could be used to form prebiotic vesicles, but the superior H-bonding ability of the ethanolamine moiety likely provides an evolutionary advantage for stable protocell formation during the fluctuating environments of early earth.

Exploring the Specific Role of Iron Center in the Catalytic Activity of Human Serum Transferrin: CTAB-Induced Conformational Changes and Sequestration by Mixed Micelles

“…Pyrene is an extensively used chromophore to determine the CMC of surfactants and surfactant mixtures. , The concentration of the pyrene was kept at 1 μM to prevent the formation of any excimer . Pyrene exhibits five well-defined fluorescence vibronic bands at 373, 378, 384, 389, and 393 nm upon excitation at 337 nm . The fluorescence intensity ratio of band I and band III (referred to as the I 1 / I 3 ratio) is most sensitive toward the polarity of the medium. , In polar environments, the intensity of the first vibronic band ( I 1 ) at 373 nm is enhanced, whereas that of the third vibronic band ( I 3 ) at 384 nm remains unaffected.…”

“…Pyrene exhibits five well-defined fluorescence vibronic bands at 373, 378, 384, 389, and 393 nm upon excitation at 337 nm . The fluorescence intensity ratio of band I and band III (referred to as the I 1 / I 3 ratio) is most sensitive toward the polarity of the medium. , In polar environments, the intensity of the first vibronic band ( I 1 ) at 373 nm is enhanced, whereas that of the third vibronic band ( I 3 ) at 384 nm remains unaffected. As displayed in Figure S5a, the plot of intensity ratio ( I 1 / I 3 ) against the concentration of surfactants contains an inflection point that defines the CMC value of that surfactant in a particular medium (here, 10 mM PB).…”

Phosphate-Based Amphiphile and Lipidated Lysine Assemble into Superior Protocellular Membranes over Carboxylate and Sulfate-Based Systems: A Potential Missing Link between Prebiotic and the Modern Era?

“…Recently, our group proposed that apart from the anionic amphiphiles, cationic amphiphiles were also important in protocell formation and catalysis. − Particularly, we have shown that a lysine-based prebiotic cationic amphiphile and anionic fatty acids may work in tandem (catanionic complex formation) to form a prebiotic membrane at low CVC and assisted in regioselective peptide bond formation . The protocell forming ability of the mixture of cationic amino acid-based amphiphiles (lysine octyl ester, LysOct) and anionic fatty acid amphiphiles (decanoic acid) led to a window of opportunities to explore the capabilities of phosphate- and sulfate-based anionic amphiphiles.…”