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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

Calculated kinetic profiles for the enzymatic production of carboxyfluorescein from CFDA, under CA catalysis, inside and outside in silico vesicle with diameter of 1.3 μm.
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life-05-00969-f013: Calculated kinetic profiles for the enzymatic production of carboxyfluorescein from CFDA, under CA catalysis, inside and outside in silico vesicle with diameter of 1.3 μm.

Mentions: Figure 13 shows the calculated kinetic profiles (30 min) for the production of CF in liposomes having rCA = 0.33, 1, or 3. When rCA = 0.33, the increment of CF concentration, and therefore of its fluorescence is faster in bulk than inside liposomes. The calculated ratio rV between the slopes (Vin/Vout) in the quasi-linear region is ~0.28, mirroring in good way the model’s rCA value (0.33). When rCA = 1 the CF concentration profiles differ only for the presence of a lag phase, due to the retardation effect exerted by the membrane. After the lag phase, in the quasi-linear region, the calculated ratio rV ~ 0.82. Finally, when rCA = 3 the increase of CF concentration is faster inside liposomes (after a lag phase). According to the model, CA-rich liposomes should soon appear more fluorescent than the background because of a faster accumulation of CF, despite the retardation effect due to the fact that CFDA must cross the membrane before reacting with encapsulated CA. In this case, the calculated rV value is ~2.1, which is a proxy value for the true rCA value (rCA = 3) [48].


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)

Calculated kinetic profiles for the enzymatic production of carboxyfluorescein from CFDA, under CA catalysis, inside and outside in silico vesicle with diameter of 1.3 μm.
© Copyright Policy
Related In: Results  -  Collection

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

life-05-00969-f013: Calculated kinetic profiles for the enzymatic production of carboxyfluorescein from CFDA, under CA catalysis, inside and outside in silico vesicle with diameter of 1.3 μm.
Mentions: Figure 13 shows the calculated kinetic profiles (30 min) for the production of CF in liposomes having rCA = 0.33, 1, or 3. When rCA = 0.33, the increment of CF concentration, and therefore of its fluorescence is faster in bulk than inside liposomes. The calculated ratio rV between the slopes (Vin/Vout) in the quasi-linear region is ~0.28, mirroring in good way the model’s rCA value (0.33). When rCA = 1 the CF concentration profiles differ only for the presence of a lag phase, due to the retardation effect exerted by the membrane. After the lag phase, in the quasi-linear region, the calculated ratio rV ~ 0.82. Finally, when rCA = 3 the increase of CF concentration is faster inside liposomes (after a lag phase). According to the model, CA-rich liposomes should soon appear more fluorescent than the background because of a faster accumulation of CF, despite the retardation effect due to the fact that CFDA must cross the membrane before reacting with encapsulated CA. In this case, the calculated rV value is ~2.1, which is a proxy value for the true rCA value (rCA = 3) [48].

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