The P0 C-terminal domain, in particular,Paclitaxel is known to interact with the acidic phosphoproteins P1 and P2 through their N-terminal domains, forming the tip of the stalk. The main functional part of the stalk in all domains of life is composed of small L12/P proteins-and these have, until now, been believed to form an evolutionarily conserved group in all species. We show in Tables 1 and 2 plus Supporting files S1 and S2, that although no sequence similarity was found between the acidic termini of T.cruzi ribosomal P proteins TcP0/TcP2b and sequences of all searched plant, microbial and viral databases by initial NCBI microbial BLAST-P at default settings, in line with prior data pointing to an architectural conservation of ribosomal P protein-structure across some life domains, repeat alignments using the BLAST-P Software and algorithms at the Swiss Institute of Biotechnology, revealed homologs of both studied C-termini of TcP0 and TcP2b with ribosomal P proteins of several eukaryotes including the animals,Pazopanib plants and protozoa. Grela and colleagues recently performed a comprehensive comparative analysis of the L12/P proteins from the three domains of life and found that bacterial and archaeo/eukaryal L12/P-proteins are not structurally related and, therefore, might not be linked evolutionarily either. Consequently, it has been suggested that proteins be regarded as analogous rather than homologous systems and probably ap-peared on the ribosomal particle in two independent events in the course of evolution. Therefore, in as much as prior insights into the structure of the ribosomes and their components at high resolution leaves no question that the overall architecture of the translational machinery of the cell has been strongly conserved in all kingdoms, it is worth noting that inter-kingdom differences among ribosomal components may inevitably exist, even though the functional significance of these structural variations has not been clarified yet.