Tadayoshi Nakashima

From Proteinoid Microsphere to Contemporary Cell: Formation of Internucleotide and Peptide Bonds by Proteinoid Particles

Proteinoid microspheres of appropriate sorts promote the conversion of ATP to adenine dinucleotide and adenine trinucleotide. Other microparticles composed of basic proteinoid and enzymically synthesized poly A cause the conversion of ATP and phenylalanine to various peptides of phenylalanine. When viewed in a context with the origin and properties of proteinoid microspheres, these results model the origin from a protocell of a more contemporary type of cell able to synthesize its own polyamino acids and polynucleotides. Related earlier experiments explain in part the origin of the genetic code and mechanism.

The assembly and properties of protobiological structures - The beginnings of cellular peptide synthesis

Abstract New data indicate that lysine-rich proteinoids have the ability to catalyze the synthesis of peptide bonds from a variety of amino acids and ATP. This capacity is evident in aqueous solution, in suspension of phase-separated complexes of lysine-rich proteinoid with acidic proteinoids, and in suspension of phase-separated particles composed of lysine-rich proteinoids with polynucleotides. Since the proteinoid complexes can contain other catalytic activities, including ability to catalyze internucleotide bond formation, we infer that the first protocells on Earth already had a number of biological types of activity.

Fractionation and characterization of an amidated thermal 1:1:1-proteinoid☆

Abstract 1. 1.|Earlier studies indicating sharply limited heterogeneity in thermal proteinoids (polyanhydro-α-amino acids containing some proportion of each amino acid common to protein) have been extended. For this purpose, another type of proteinoid has been amidated and the resultant polymer fractionated on DEAE-cellulose. Six relatively symmetrical major peaks were obtained. After further purification, only small compositional differences between three of the fractions and the crude polymer were found in amino acid analyses. 2. 2.|The three fractions studied were individually examined further for heterogeneity by Sephadex exclusion and Bio-Gel exclusion, by high-voltage electrophoresis, and by ultracentrifugal analysis. The total results and related inferences are interpreted to signify a high degree of compositional uniformity throughout the original polymer. 3. 3.|Partial hydrolyzates of the three purified fractions yield ‘fingerprints’ which are similar and which contain 39–41 peaks in chromatograms. When viewed in the light of the compositional uniformity and earlier results indicating spontaneous ordering of residues in the synthesis of proteinoids, a high degree of sequential uniformity in the total polymer is suggested. 4. 4.|The significance of these results in the context of evolution of protein molecules is discussed.

Formation of peptides from amino acids by single or multiple additions of ATP to suspensions of nucleoproteinoid microparticles

When lysine-rich proteinoid, which catalyzes the formation of peptides from amino acids and ATP, is complexed with acidic proteinoid to form microspheres of mixed constitution, the normal synthesis by basic proteinoid alone is multiplied several-fold. The product consists not only of small peptides but also of a high-molecular-weight fraction of substituted proteinoid. Suspensions of particles of lysine-rich proteinoid complexed with polyadenylic acid catalyze the synthesis of peptides from each of the amino acids tested with ATP. When equimolar solutions of mixtures of glycine and phenylalanine with ATP are tested in suspensions of complexes of lysine-rich proteinoid and each of various polyribonucleotides, both homopeptides and heteropeptides are produced. Glycylphenylalanine or phenylalanylglycine is the principal product; the preference is related to which polyribonucleotide is in the complex. The rate of conversion of amino acid to peptide is a function of whether ATP is added in a single batch or in repeated amounts adding to the same amount as in the single batch. Related experiments indicate a relatively rapid initial rate of decay of ATP in the system. These results are discussed relative to the mechanisms for continuous generation in modern organisms, as are the results in peptide formation.

Effects of several factors on chemical condensation of mixed amino acid adenylates

Protein synthesis, dialysis and Mg ion concentration effects on chemical condensation of mixed amino acid adenylates

Endogenously Determined Variants as Precursors of Substrates for Natural Selection

The emergence of living individuals would seem to have been synonymous with what is usually referred to as the origin of life. Experiments in the formation of protoorganisms suggest, however, that individuality can be identified for an even earlier molecular stage in immediate precursors of those first organisms. Those precursors, which avidly assemble to “laboratory protocells” in the presence of water, are known as proteinoids, or are indexed in Chemical Abstracts as thermal proteins.

Experimental models of communication at the molecular and microsystemic levels.

Communication at both the macromolecular and the (supramacromolecular) microsystemic levels has been demonstrated in artificial polymers and artificial systems. These phenomena are models for communication in evolving and contemporary systems. The significance of a combination of communication at the two levels is emphasized.