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Physical Routes to Primitive Cells: An Experimental Model Based on the Spontaneous Entrapment of Enzymes inside Micrometer-Sized Liposomes.

D'Aguanno E, Altamura E, Mavelli F, Fahr A, Stano P, Luisi PL - Life (Basel) (2015)

Bottom Line: We have reported that proteins and ribosomes can be encapsulated very efficiently, against statistical expectations, inside a small number of liposomes.Moreover the transcription-translation mixture, which realistically mimics a sort of minimal metabolic network, can be functionally reconstituted in liposomes owing to a self-concentration mechanism.Here we firstly summarize the recent advancements in this research line, highlighting how these results open a new vista on the phenomena that could have been important for the formation of functional primitive cells.

View Article: PubMed Central - PubMed

Affiliation: Science Department, Roma Tre University, Viale G. Marconi 446, I-00146 Rome, Italy. Alfred.Fahr@uni-jena.de.

ABSTRACT
How did primitive living cells originate? The formation of early cells, which were probably solute-filled vesicles capable of performing a rudimentary metabolism (and possibly self-reproduction), is still one of the big unsolved questions in origin of life. We have recently used lipid vesicles (liposomes) as primitive cell models, aiming at the study of the physical mechanisms for macromolecules encapsulation. We have reported that proteins and ribosomes can be encapsulated very efficiently, against statistical expectations, inside a small number of liposomes. Moreover the transcription-translation mixture, which realistically mimics a sort of minimal metabolic network, can be functionally reconstituted in liposomes owing to a self-concentration mechanism. Here we firstly summarize the recent advancements in this research line, highlighting how these results open a new vista on the phenomena that could have been important for the formation of functional primitive cells. Then, we present new evidences on the non-random entrapment of macromolecules (proteins, dextrans) in phospholipid vesicle, and in particular we show how enzymatic reactions can be accelerated because of the enhancement of their concentration inside liposomes.

No MeSH data available.


Related in: MedlinePlus

Protein synthesis inside conventional liposomes. (a) Components and functions of the PURE systems (reproduced from [27] with the permission of Elsevier); (b) fluorescence versus time profiles of eGFP producing vesicles (+DNA) and negative control (−DNA) (reproduced from [9] with the permission of Wiley).
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life-05-00969-f003: Protein synthesis inside conventional liposomes. (a) Components and functions of the PURE systems (reproduced from [27] with the permission of Elsevier); (b) fluorescence versus time profiles of eGFP producing vesicles (+DNA) and negative control (−DNA) (reproduced from [9] with the permission of Wiley).

Mentions: Transcription-translation (TX-TL) network is the core set of reactions in minimal cells. The genes that encode such network constitute about 60% of the “minimal genome” [24,25], and TX-TL reactions can be carried out in vitro by using cell extracts (for example, from Escherichia coli) or reconstituted systems. For these reasons, the construction of semi-synthetic minimal cell encapsulating TX-TL mixtures is a quite advantageous way to mimic primitive cells of minimal yet not negligible complexity. The PURE system (Figure 3A) is a reconstituted TX-TL kit composed by the minimal number of components (about 80 macromolecules, two dozen small molecules, organic buffer, and inorganic salts) required for synthesizing a protein starting from DNA [26,27].


Physical Routes to Primitive Cells: An Experimental Model Based on the Spontaneous Entrapment of Enzymes inside Micrometer-Sized Liposomes.

D'Aguanno E, Altamura E, Mavelli F, Fahr A, Stano P, Luisi PL - Life (Basel) (2015)

Protein synthesis inside conventional liposomes. (a) Components and functions of the PURE systems (reproduced from [27] with the permission of Elsevier); (b) fluorescence versus time profiles of eGFP producing vesicles (+DNA) and negative control (−DNA) (reproduced from [9] with the permission of Wiley).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390888&req=5

life-05-00969-f003: Protein synthesis inside conventional liposomes. (a) Components and functions of the PURE systems (reproduced from [27] with the permission of Elsevier); (b) fluorescence versus time profiles of eGFP producing vesicles (+DNA) and negative control (−DNA) (reproduced from [9] with the permission of Wiley).
Mentions: Transcription-translation (TX-TL) network is the core set of reactions in minimal cells. The genes that encode such network constitute about 60% of the “minimal genome” [24,25], and TX-TL reactions can be carried out in vitro by using cell extracts (for example, from Escherichia coli) or reconstituted systems. For these reasons, the construction of semi-synthetic minimal cell encapsulating TX-TL mixtures is a quite advantageous way to mimic primitive cells of minimal yet not negligible complexity. The PURE system (Figure 3A) is a reconstituted TX-TL kit composed by the minimal number of components (about 80 macromolecules, two dozen small molecules, organic buffer, and inorganic salts) required for synthesizing a protein starting from DNA [26,27].

Bottom Line: We have reported that proteins and ribosomes can be encapsulated very efficiently, against statistical expectations, inside a small number of liposomes.Moreover the transcription-translation mixture, which realistically mimics a sort of minimal metabolic network, can be functionally reconstituted in liposomes owing to a self-concentration mechanism.Here we firstly summarize the recent advancements in this research line, highlighting how these results open a new vista on the phenomena that could have been important for the formation of functional primitive cells.

View Article: PubMed Central - PubMed

Affiliation: Science Department, Roma Tre University, Viale G. Marconi 446, I-00146 Rome, Italy. Alfred.Fahr@uni-jena.de.

ABSTRACT
How did primitive living cells originate? The formation of early cells, which were probably solute-filled vesicles capable of performing a rudimentary metabolism (and possibly self-reproduction), is still one of the big unsolved questions in origin of life. We have recently used lipid vesicles (liposomes) as primitive cell models, aiming at the study of the physical mechanisms for macromolecules encapsulation. We have reported that proteins and ribosomes can be encapsulated very efficiently, against statistical expectations, inside a small number of liposomes. Moreover the transcription-translation mixture, which realistically mimics a sort of minimal metabolic network, can be functionally reconstituted in liposomes owing to a self-concentration mechanism. Here we firstly summarize the recent advancements in this research line, highlighting how these results open a new vista on the phenomena that could have been important for the formation of functional primitive cells. Then, we present new evidences on the non-random entrapment of macromolecules (proteins, dextrans) in phospholipid vesicle, and in particular we show how enzymatic reactions can be accelerated because of the enhancement of their concentration inside liposomes.

No MeSH data available.


Related in: MedlinePlus