Liposome-assisted selective polycondensation of α-amino acids and peptides

Hitz, Thomas; Luisi, Pier Luigi

doi:10.1002/1097-0282(2000)55:5<381::aid-bip1012>3.0.co;2-q

Cited by 28 publications

(24 citation statements)

References 23 publications

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“…Although the formation of a five-membered ring may be easier than that of a six-membered one, the difference is unlikely to compensate for a change in pK A of 8 units. The prevailing trans configuration of the amide bond and the kinetic barrier to rotation therefore constitute (Blocher et al 1999(Blocher et al , 2000Hitz and Luisi 2000), prompted us to undertake an analysis of the outcome of the use of other reagents capable of activating the free dipeptide substrate or directly of that of pre-activated forms (Table 1). In addition to being precursors of mixed anhydrides, reagents such as EEDQ or IBCF (iso-butyl chloroformate) are expected to yield urethanes owing to the nucleophilic character of the N-terminal amino group (pK a~8 ).…”

Section: Resultsmentioning

confidence: 99%

“…We considered therefore that free dipeptides represent a specific case regarding this kind of activation since both the neighbouring oxygen of the amide group and the terminal amine constitute nucleophiles located at a favourable position for a fast intramolecular reaction (Kirby 1980). Though no explanation was given to these observations, the group of Luisi indeed observed that the activation of hydrophobic di-tryptophan in the presence of zwitterionic POPC (POPC=1-palmitoyl-2-oleoylphosphatidylcholine) vesicles (Blocher et al 1999(Blocher et al , 2000 or positively charged Arg-Trp in the presence of negatively charged mixed DOPA/POPC (DOPA=1,2-dioleyl phosphatidic acid) vesicles (Blocher et al 2000;Hitz and Luisi 2000) yielded tetramers and higher oligomers rather than diketopiperazines that were marginally formed. We decided therefore to investigate the possibility that the pathway involving 5(4H)-oxazolones as intermediates could prevent DKP formation (Scheme 2).…”

Section: Introductionmentioning

confidence: 99%

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The Activation of Free Dipeptides Promoted by Strong Activating Agents in Water Does not Yield Diketopiperazines

Beaufils

Jepaul

Liu

et al. 2015

Orig Life Evol Biosph

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The activation of dipeptides was studied in the perspective of the abiotic formation of oligopeptides of significant length as a requirement for secondary structure formation. The formation of piperazin-2,5-diones (DKP), previously considered as a dead end when activating free dipeptides, was shown in this work to be efficiently suppressed when using strong activating agents (e.g., carbodiimides). This behaviour was explained by the fast formation of a 5(4H)-oxazolone intermediate at a rate that exceeds the time scale of the rotation of the peptide bond from the predominant trans-conformation into the cis-isomer required for DKP formation. No DKP was observed when using strong activating agents whereas phosphate mixed anhydrides or moderately activated esters were observed to predominantly yield DKP. The DKP side-reaction no longer constitutes a drawback for the C-terminus elongation of peptides. These results are considered as additional evidence that pathways involving strong activation are required to drive the emergence of living entities rather than close to equilibrium processes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Activation of Free Dipeptides Promoted by Strong Activating Agents in Water Does not Yield Diketopiperazines

Beaufils

Jepaul

Liu

et al. 2015

Orig Life Evol Biosph

View full text Add to dashboard Cite

show abstract

“…Among them, a vesicle is an enclosed bilayered structure with solvent molecules encapsulated inside and is an analogue to a biological cell. Therefore, vesicles find extensive applications in artificial cells [5] , drug delivery [6] , biosensor [7] , and micro-reactor [8] and so on. Since vesicle formation occurs within a microsecond time scale and a submicron length scale, it is not easy to investigate the dynamics in details by conventional experimental methods [9] .…”

Section: Introductionmentioning

confidence: 99%

Dissipative particle dynamics simulation study of the bilayer-vesicle transition

Guo

2008

Sci. China Ser. B-Chem.

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A bilayer structure is an important immediate for the vesicle formation. However, the mechanism for the bilayer-vesicle transition remains unclear. In this work, a dissipative particle dynamics (DPD) simulation method was employed to study the mechanism of the bilayer-vesicle transition. A coarse-grained model was built based on a lipid molecule termed dimyristoylphosphatidylcholine (DMPC). Simulations were performed from two different initial configurations: a random dispersed solution and a tensionless bilayer. It was found that the bilayer-vesicle transition was driven by the minimization of the water-tail hydrophobic interaction energy, and was accompanied with the increase of the position entropy due to the redistribution of water molecules. The bulk pressure was reduced during the bilayer-vesicle transition, suggesting the evolved vesicle morphology was at the relatively low free energy state. The membrane in the product vesicle was a two-dimensional fluid. It can be concluded that the membrane of a vesicle is not interdigitated and most of the bonds in lipid chains are inclined to orient along the radical axis of the vesicle.vesicle, dissipative particle dynamics, lipid

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“…templates and catalysts) could have been randomly encapsulated inside of spontaneously forming vesicles. Joint uptake of the catalytic molecules, reaction templates and substrates could lead to active enzymatic reactions inside of synthetic vesicles (Segré et al 2000;Hitz and Luisi 2001;Pietrini and Luisi 2004;Noireaux and Libchaber 2004;Apel and Deamer 2005;Sacerdote and Szostak 2005;Sunami et al 2006). Thus it is possible in principle that functional primitive cellular assemblies could have formed via random encapsulation of trans-acting molecular components and their reaction substrates.…”

Section: Encapsulation Of Biotic Polymers and Emergence Of Complexitymentioning

confidence: 99%

Protein-mediated Selective Enclosure of Early Replicators Inside of Membranous Vesicles: First Step Towards Cell Membranes

Laiterä

Lehto

2009

Orig Life Evol Biosph

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Containment in cell membranes is essential for all contemporary life, and apparently even the earliest life forms had to be somehow contained. It has been postulated that random enclosure of replicating molecules inside of spontaneously assembled vesicles would have formed the initial cellular ancestors. However, completely random re-formation or division of such primitive vesicles would have abolished the heritability of their contents, nullifying any selective advantage to them. We propose that the containment of the early replicators in membranous vesicles was adopted only after the invention of genetically encoded proteins, and that selective enclosure of target molecules was mediated by specific proteins. A similar containment process is still utilised by various RNA- and retroviruses to isolate their replication complexes from the host's intracellular environment. Such selective encapsulation would have protected the replicators against competitor and parasitic sequences, and provided a strong positive selection within the replicator communities.

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Liposome-assisted selective polycondensation of α-amino acids and peptides

Cited by 28 publications

References 23 publications

The Activation of Free Dipeptides Promoted by Strong Activating Agents in Water Does not Yield Diketopiperazines

The Activation of Free Dipeptides Promoted by Strong Activating Agents in Water Does not Yield Diketopiperazines

Dissipative particle dynamics simulation study of the bilayer-vesicle transition

Protein-mediated Selective Enclosure of Early Replicators Inside of Membranous Vesicles: First Step Towards Cell Membranes

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