Compartmentalization in proteinoid microspheres

Proteinoid microspheres with stable internal compartments and internal structure are made from acidic proteinoid and basic proteinoid with calcium. The populations of microspheres are characterized by a wide diversity of structure. A model of primitive intracellular communication is suggested by the observed movement of internal particles between compartments of a multicompartmentalized unit. Differential response to pH change and to temperature change has been demonstrated within one population and suggests one mode of adaptive selection among primordial cell populations.

Polycondensation of alpha-amino acids by pyrosulfuric acid

The thermal polycondensation of amino acids common to protein is promoted at 80 degrees C by pyrosulfuric acid. This is in contrast to the noncondensation at 100 degrees C in the presence of concentrated sulfuric acid. These results are in accord with an anhydride mechanism, as proposed earlier for copolycondensation promoted by polyphosphoric acid. The amino acid composition, molecular weight, near-homogeneity, are infrared absorption of the polymer formed are described. The potential significance of planetary pyrosulfuric acid is discussed.

Interactions between diverse proteinoids and microspheres in simulation of primordial evolution

Experiments demonstrating an incorporation of different enzymelike activities into a single preparation of proteinoid microspheres provide a conceptual basis for the primitive lengthening of protometabolic pathways. An enhancement of one enzymelike activity by another proteinoid in the same microsphere has been found. This effect, plus the pathway-lengthening propensity of combinations of microspheres, indicates selective advantages contributing to adaptive protoselection. Data reported in this paper also bring into purview the concept of internally controlled variation. Inferences are derived for the origin of protosexuality in protocells. When allowance is made for a closer relationship to the environment than that needed in contemporary selection, the fundamental mechanistic requirements of protoevolution are regarded as met by the proteinoid microsphere.

Linkages in thermal copolymers of lysine

The thermal copolymerization of lysine with other alpha-amino acids has been studied further. The identity of the second amino acid influences various properties of the polymer obtained, including the proportion of alpha and epsilon linkages of lysine. A review of linkages in proteinoids indicated alpha and beta linkages for aspartic acid, alpha and gamma linkages for glutamic acid, alpha and epsilon linkages for lysine, and alpha linkages for other amino acids. Thermal proteinoids are thus more complex in types of linkage than are proteins.

The evolutionary significance of phase-separated microsystems

The source, preparation, and properties of phase-separated systems such as lipid layers, coacervate droplets, sulphobes, and proteinoid microspheres are reviewed. These microsystems are of interest as partial models for the cell and as partial or total models for the protocell. Conceptual benefits from study of such models are: clues to experiments on origins, insights into principles of action and, in some instances, presumable models of the origin of the protocell. The benefits to evolution of organized chemical units are many, and can in part be analyzed. Ease of formation suggests that such units would have arisen early in primondiae organic evolution. Integration of these various concepts and the results of consequent experiments have contributed to the developing theory of the origins of primordial and of contemporary life.

A model for the origin of stable protocells in a primitive alkaline ocean

When a mixture of the eighteen proteinous amino acids are suitably heated in the dry state with seawater salts, a copolyamino acid results. One fraction of this polymer is found, through isoelectric focusing, to consist of a mixture of acidic and basic proteinoids, each of sharply limited heterogeneity. When one fraction of the seawater proteinoid is dissolved in hot water, and the solution is cooled, proteinoid microspheres result. These have properties in common with simpler types, but also stable at pH values to 9, in common with microspheres prepared by mixing acidic and basic proteinoids. These processes thus constitute a simple model for the origin of a protocell stable in a primitive alkaline ocean.

Selective condensation of aminoacyl adenylates by nucleoproteinoid microparticles (prebiotic-lysine-model system-genetic code)

Microparticles composed of each of four enzymically synthesized homopolynucleotides and the same lysine-rich proteinoid have been found to influence the condensation of the AMP-anhydrides of each of four amino acids. The conditions of preparation of the particles and other variables of the experiments control the types of reaction. When a specified set of conditions was identified empirically, the incorporation favored the amino acids whose present-day codons are related to the homopolynucleotide in the particle.