Excitable artificial cells of proteinoid

Przybylski, A; Fox, Sidney W.

doi:10.1007/bf02783764

Cited by 25 publications

(23 citation statements)

References 8 publications

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“…Even the simplest mechanisms, such as temperature cycling that creates defects during the liquid/gel phase transition in membranes [76,77] or other types of defects [78], might have increased ion transport rates across the earliest phospholipid membranes. Increased ion permeation due to defects was observed not only in lipid bilayers, but also in protenoid membranes assembled of thermal polymers of amino acids, such as aspartic or glutamic acid [79,80]. However, none of these processes are fast and reliable.…”

Section: Membrane Proteinsmentioning

confidence: 99%

Flexible Proteins at the Origin of Life

Pohorille

Wilson

Shannon

2017

Life

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Almost all modern proteins possess well-defined, relatively rigid scaffolds that provide structural preorganization for desired functions. Such scaffolds require the sufficient length of a polypeptide chain and extensive evolutionary optimization. How ancestral proteins attained functionality, even though they were most likely markedly smaller than their contemporary descendants, remains a major, unresolved question in the origin of life. On the basis of evidence from experiments and computer simulations, we argue that at least some of the earliest water-soluble and membrane proteins were markedly more flexible than their modern counterparts. As an example, we consider a small, evolved in vitro ligase, based on a novel architecture that may be the archetype of primordial enzymes. The protein does not contain a hydrophobic core or conventional elements of the secondary structure characteristic of modern water-soluble proteins, but instead is built of a flexible, catalytic loop supported by a small hydrophilic core containing zinc atoms. It appears that disorder in the polypeptide chain imparts robustness to mutations in the protein core. Simple ion channels, likely the earliest membrane protein assemblies, could also be quite flexible, but still retain their functionality, again in contrast to their modern descendants. This is demonstrated in the example of antiamoebin, which can serve as a useful model of small peptides forming ancestral ion channels. Common features of the earliest, functional protein architectures discussed here include not only their flexibility, but also a low level of evolutionary optimization and heterogeneity in amino acid composition and, possibly, the type of peptide bonds in the protein backbone.

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Section: Membrane Proteinsmentioning

confidence: 99%

Flexible Proteins at the Origin of Life

Pohorille

Wilson

Shannon

2017

Life

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“…One proteinoid is completely different from another, by the fact that they are made of different amino acid monomers. This fact provides each proteinoid special features, and possibly influences the character of particles made from it [28][29][30][31]. Up until now, most, if not all, of the reported proteinoids in the literature were synthesized from at least seven amino acids and possessed relatively low molecular weights.…”

Section: Introductionmentioning

confidence: 99%

Engineered Narrow Size Distribution High Molecular Weight Proteinoids, Proteinoid-Poly(L-Lactic Acid) Copolymers and Nano/Micro-Hollow Particles for Biomedical Applications

Kolitz‐Domb¹

2014

J Nanomed Nanotechnol

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Proteinoids are unusual polymers formed by thermal condensation of amino acids. Several types of proteinoids made of one to three different amino acids, in absence or presence, of low molecular weight poly(L-lactic acid) (PLLA), were synthesized. The polymerization kinetics, molecular weights and physical and mechanical properties of these proteinoids were elucidated. The ability to obtain several high-MW durable proteinoids, by using different amino acids as building blocks, along with incorporating PLLA in their structure, yields a new perspective of biodegradable polymers and polymer particles. Under suitable gentle conditions, the proteinoids can self-assemble to form nanoand micron-sized hollow particles of relatively narrow size distribution. This self-assembly process was used for encapsulation of different molecules within the produced proteinoid particles. One of the encapsulated materials used was indocyanine green (ICG), a known and FDA-approved near-IR dye used for medical cancer diagnosis. The ICG-encapsulated proteinoid particles were tested for biodistribution in mice. The proteinoid particles are nontoxic and stable; hence, they may be excellent candidates for various biomedical applications, e.g., cell labeling and separation, controlled release, drug targeting, etc. Scheme 1: Thermal polymerization of amino acids through pyroglutamic acid catalysis. Journal of Nanomedicine & Nanotechnology J o u rna l of N a n o m ed icine & N a n o te chnolo g y

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“…Therefore, it is quite natural to believe that the action potential is not observed in the artificial system having neither ion channels nor pumps. Contrary to such a quite natural thought, action potential-like potential has been repeatedly observed in the artificial systems in which no ion channels or pumps were embedded [ 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ].…”

Section: Introductionmentioning

confidence: 99%

“…Proteinoid is a tiny sphere consisting of amino acids. It was first created by Sidney Fox [ 31 , 32 , 34 , 35 , 40 ]. Scientists regard it as a protocell or something similar to the protocell.…”

Section: Introductionmentioning

confidence: 99%

Ling’s Adsorption Theory as a Mechanism of Membrane Potential Generation Observed in Both Living and Nonliving Systems

2016

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The potential between two electrolytic solutions separated by a membrane impermeable to ions was measured and the generation mechanism of potential measured was investigated. From the physiological point of view, a nonzero membrane potential or action potential cannot be observed across the impermeable membrane. However, a nonzero membrane potential including action potential-like potential was clearly observed. Those observations gave rise to a doubt concerning the validity of currently accepted generation mechanism of membrane potential and action potential of cell. As an alternative theory, we found that the long-forgotten Ling’s adsorption theory was the most plausible theory. Ling’s adsorption theory suggests that the membrane potential and action potential of a living cell is due to the adsorption of mobile ions onto the adsorption site of cell, and this theory is applicable even to nonliving (or non-biological) system as well as living system. Through this paper, the authors emphasize that it is necessary to reconsider the validity of current membrane theory and also would like to urge the readers to pay keen attention to the Ling’s adsorption theory which has for long years been forgotten in the history of physiology.

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Excitable artificial cells of proteinoid

Cited by 25 publications

References 8 publications

Flexible Proteins at the Origin of Life

Flexible Proteins at the Origin of Life

Engineered Narrow Size Distribution High Molecular Weight Proteinoids, Proteinoid-Poly(L-Lactic Acid) Copolymers and Nano/Micro-Hollow Particles for Biomedical Applications

Ling’s Adsorption Theory as a Mechanism of Membrane Potential Generation Observed in Both Living and Nonliving Systems

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