Singularidades orgânicas: análise das adaptações das proteínas ribossômicas universais de organismos extremófilos halófilos dos domínios archaea e bacteria

Abstract

The group of halophiles brings together organisms that, through structural and physiological adaptations, can survive in environments with extreme salinity . One of the great characteristics pointed out about the molecular adaptations of halophiles relates to the acid character of most of their studied proteins. It is known that ribosomes in all forms of life are formed by interactions between various proteins and RNA molecules and one of the biological roles of ribosomal proteins is neutralization of negative ribosomal RNA charges. The studies of the primary sequences of these proteins in mesophilic organisms point out that one of their main characteristics is the high content of basic amino acids, important for the stabilization of the ribonucleoprotein complex. Using this data as a starting point, the present study aimed to evaluate the adaptations of ribosomal proteins of halophiles organisms in the Archaea and Bacteria domains, through basic statistical analysis based on primary sequence data available at NCBI. With a total of 885 species of extreme halophiles organisms belonging to two domains of prokaryotic life: Archaea (260) and Bacteria (625), and 190 species of non-extreme species used as control, were extracted a total of 17,255 associated sequences as 34 universal ribosomal proteins. After quantifying the amino acids in the multiphase files corresponding to each group, statistical tests were used to evaluate and compare their amino acid composition. As a result, we obtained two profiles for the ribosomal proteins of halophiles: the Archean proteins, as well as the pattern presented in previous studies, presented higher percentages of acidic amino acids and lower percentages of aromatic and aliphatic hydrophobic amino acids compared to the control mesophilic sequences; however, the sequences of the bacterial halophiles did not show statistically significant differences to their control group. W e conclude that the ribosomal proteins of halophiles, mainly from the Archaea domain, have an expressively acidic composition, due to the close interaction between protein elements and ribonucleic acids.