RNP-world: The ultimate essence of life is a ribonucleoprotein process

Abstract

The fundamental essence of life is based on process of interaction between nucleic acids and proteins. In a prebiotic world, amino acids, peptides, ions, and other metabolites acted in protobiotic routes at the same time on which RNAs performed catalysis and self-replication. Nevertheless, it was only when nucleic acids and peptides started to interact together in an organized process that life emerged. First, the ignition was sparked with the formation of a Peptidyl Transferase Center (PTC), possibly by concatenation of proto-tRNAs. This molecule that would become the catalytic site of ribosomes started a process of self-organization that gave origin to a protoorganism named FUCA, a ribonucleic ribosomal-like apparatus capable to polymerize amino acids. In that sense, we review hypotheses about the origin and early evolution of the genetic code. Next, populations of open biological systems named progenotes were capable of accumulating and exchanging genetic material, producing the first genomes. Progenotes then evolved in two paths: some presented their own ribosomes and others used available ribosomes in the medium to translate their encoded information. At some point, two different types of organisms emerged from populations of progenotes: the ribosome-encoding organisms (cells) and the capsid-encoding organisms (viruses).

The ‘LUCAN’ Concept, the Latest Universally Common Ancestral Network Stage of Early Life: From Molecular Cooperation and Horizontal Symbiosis to the Escape of Vertically Stabilized Lineages of Particulate Viral Propagules and Cellular Organisms

“…Moreover, he extends similar arguments with regard to Eukaryogenesis from the collective Progenote State no matter whether Eukarya shared a common ancestor with Archaea in general or Asgardarchaeota in particular [327]. The Prosdocimi/Farias group, too, is taking seriously the possibility that cellularization from an acellular Progenote State occurred several times independently for different cell types [129,328].…”

“…The co-emergent RNA-peptide alliance is part of an RNP World scenario as a primordial model without requiring a preceding RNA World stage to start with [128,129]. The bi-partite coevolution then consolidated the functional utility of some prebiotic peptides -in ribonucleoprotein (RNP) complexes with RNA -as "molecular hubs in the origin of life" [79].…”

“…The higher-level units must appear as the result of coevolution of units at the lower level" [92]. This caveat in fact applies to any major evolutionary transition that rests upon the coevolutionary emergence of complex innovations composed of many interacting parts, as prominently represented by the emergence and subsequent optimization of the genetic coding and translation systems, which presumably occurred under RNP World conditions [129].…”

Rules governing the genetic code degeneracy/redundancy and spatial organization of the codon informative properties

“…The relational model of the structure of the standard genetic code analyzed by Konjevoda and Štambuk ( 29) is a valuable attempt to unify these and other evolving studies. Other authors emphasize the role of tRNA in the origin and evolution of the genetic code, highlighting the interactions between aminoacyl-tRNA synthetases and different tRNA domains, an operational code of tRNA aminoacylation and a standard tRNA code composed of 46 anticodons (46)(47)(48)(49)(50)(51)(52).…”