The RNP world is a hypothesized intermediate period in the

origin of life In biology, abiogenesis (from a- 'not' + Greek bios 'life' + genesis 'origin') or the origin of life is the natural process by which life has arisen from non-living matter, such as simple organic compounds. The prevailing scientific hypothes ...

characterized by the existence of

ribonucleoprotein Nucleoproteins are proteins conjugated with nucleic acids (either DNA or RNA). Typical nucleoproteins include ribosomes, nucleosomes and viral nucleocapsid proteins. Structures Nucleoproteins tend to be positively charged, facilitating inte ...

s. The period followed the hypothesized

RNA world The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existenc ...

and ended with the formation of DNA and contemporary proteins. During this time, RNA molecules continued to perform many essential functions, but began to synthesize

peptides Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. ...

, which eventually assumed most of the function of those RNA molecules (i.e. became ''proteins''), leading to life as we know it.{{Cite journal, last=Cech, first=Thomas R., date=2009-02-20, title=Crawling Out of the RNA World, journal=Cell, language=en, volume=136, issue=4, pages=599–602, doi=10.1016/j.cell.2009.02.002, pmid=19239881, s2cid=13933577, issn=0092-8674, doi-access=free Principle of concept Thomas Cech in 2009 proposed the existence of the RNP world after his observation of apparent differences in the composition of catalysts in the two most fundamental processes that maintain and express genetic systems. DNA replication and transcription— are accomplished by purely protein polymerases.

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of synthesizing a protein. mRNA is created during the ...

splicing and protein synthesis—are

catalyzed Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycl ...

by RNP complexes (the

spliceosome A spliceosome is a large ribonucleoprotein (RNP) complex found primarily within the nucleus of eukaryotic cells. The spliceosome is assembled from small nuclear RNAs ( snRNA) and numerous proteins. Small nuclear RNA (snRNA) molecules bind to sp ...

and ribosome). Such observation was consistent with RNA word theory. RNA as an older molecule from DNA had a more ancient hybrid RNA-protein-based structure of its maintenance system. This could imply a gradual replacement of catalysis machines from RNA to proteins, with

ribonucleoproteins Nucleoproteins are proteins conjugated with nucleic acids (either DNA or RNA). Typical nucleoproteins include ribosomes, nucleosomes and viral nucleocapsid proteins. Structures Nucleoproteins tend to be positively charged, facilitating int ...

and nucleotide-based cofactors being relics of this era.

References

Ribonucleoproteins RNA DNA Peptides Proteins