Universidade Federal Da ParaíbaCentro de Ciências Exatas e da Natureza

Departamento de Biologia Molecular

Sávio Torres de FariasPh.D in Genetics

RNA World

Protein World

Ribonucleoproteic World

tRNA begins the process

tRNA gave origin to mRNA and rRNA by structural changes.

Origin of Translation

Translation was the attractor of the system

The first proteins were RNA binders.

Translation

Housekeep pathways

Complex metabolic pathways

Eigen (1978) proposed that the first coding system were formatted for codons with the pattern RNY

In the modern genetic code, the codons with this pattern codifies to:

Ala, Gly, Ser, Thr, Asn, Asp, Val and Ile

The tRNA molecules were obtained in a total of 9758 from the tRNA database (http://trnadb.bioinf.uni-leipzig.de).

361 organisms distributed in the three domains of life.

35 ancestral sequences were generated by maximum likelihood for 22 types of tRNA, 20 to canonical tRNAs, an initiator tRNA and a tRNA for selenocysteine .

Phylogenetic trees to ancestral sequences were constructed by Maximum Likelihood method and the Tamura-Nei + gamma distribution was used as the evolutionary model.

The statistical analysis method used was bootstrap with 1000 replicates.

Hyphotesis tRNA can be translated

Methodology RNY tRNAs like mRNA Shuffle the tRNA ancestor to RNY code in

all combinations (2x8, 3x8 and 4x8). Analyze by Blastx

Elongation factor 1-alpha - RNA transport Elongation factor 4 - mRNA-translation-assisting tRNA uridine 5-carboxymethylaminomethyl

modification 60S ribosomal protein L3 – Ribosome 60S ribosomal protein L7a 60S ribosomal protein L27a-1 60S ribosomal protein L27a-2/4 60S ribosomal protein L27a-3 50S ribosomal protein L10 Methionyl-tRNA formyltransferase

Lysyl-tRNA synthetase Asparagine--tRNA synthetase Glutamyl-tRNA synthetase Leucyl-tRNA synthetase Valyl-tRNA synthetase Phenylalanine—tRNA synthetase Beta RNA methyltransferase – tRNA methylation

Korobeinikova et al 2012

Korobeinikova et al 2012

Korobeinikova et al 2012

DNA-directed RNA polymerase or RNA-directed RNA polymerase

Diaminopimelato epimerase L-asparaginase ATP phosporibosyltransferase Histidinol-phosphate aminotransferase 4-aminobutyrate aminotransferase Ornithine decarboxilase antizyme N-acetyl-gama-glutamyl-phosphate redutase Homoserine kinase Aromatic-amino acid aminotransferase Ornithine carbomyltransferase Tryptophan synthase alpha chain.

Puntative ribose/galactose/methylgalactose import

Glycerate kinase Triose phosphate isomerase Beta-glucosidase A Glucose 6-phosphate 1-dehydrogenase 2 Glucose 6-phosphate isomerase Phosphoglycerate kinase Glyceral 3-phosphate dehydrogenase Transketolase Alpha-galactosidase.

Fatty acid synthase CoA mutase Phosphate acyltransferase Lycopene cyclase 3 beta-hydroxisteroid dehydrogenase

Thymidylate kinase Cytidine deaminase Uridylate kinase Orotidine 5-phosphate decarboxilase Dihydroorotate dehydrogenase Phosphoribosylformylglycinamidine cyclo-ligase phosphoribosylglycinamidine synthase.

Table 1: Positions which each tRNA ancestor had alignment with the region V of the 23S ribosomal subunit and the percentage of the alignment.

LeutRNA-SertRNA-HistRNA-ProtRNA-TyrtRNA-PhetRNA-GlntRNA-GlytRNA-LystRNA

Figure 1: Alignment of the sequence of ancestral tRNAs against Peptidyl Transferase Center from Thermus thermophilus. the positions that have indentity. indicate the catalytic position conserved. 50,53 % similarity. (Farias et al, 2014)

Organism CorrelationT. thermophilus 0,873444626H. marismortui 0,540474457

E. coli 0,514957865D. radiodurans 0,866238878

C. jejuni 0,784045276B. subtilis 0,837122165

B. burgdoferi 0,599684609

Prebiotic compounds

Translation

Peptides synthesis

System stabilization

emergence of new metabolic pathways

selective pressureProvides substrate

tRNA gave origin to the first genes

tRNA gave origin to catalytic center of the ribosome

tRNAs organized the translation system

The metabolic pathways emerged to provide substract for the translation system

Laboratório de Genética Evolutiva Paulo Lemisnk (Universidade Federal da Paraíba/Brasil) Sávio Torres de Farias Thais Gaudêncio Rego Daniel Antonino

Theoretical Biology Group (Universidade Nacional Autônoma de México/México) Marco José Miryam Palacios Perez