Identification of cellular proteins associated with human cytomegalovirus (HCMV) DNA replication suggests novel cellular and viral interactions.

Upon entry of Human cytomegalovirus (HCMV) into the host cell, the viral genome is transported to the nucleus where it serves as a template for transcription and genome replication. Production of new viral genomes is a coordinated effort between viral and cellular proteins. While the core replication proteins are encoded by the virus, additional cellular proteins support the process of genome synthesis. We used accelerated native isolation of proteins on nascent DNA (aniPOND) to study protein dynamics on nascent viral DNA during HCMV infection. Using this method, we identified specific viral and cellular proteins that are associated with nascent viral DNA. These included transcription factors, transcriptional regulators, DNA damage and repair factors, and chromatin remodeling complexes. The association of these identified proteins with viral DNA was confirmed by immunofluorescent imaging, chromatin-immunoprecipitation analyses, and shRNA knockdown experiments. These data provide evidence for the requirement of cellular factors involved in HCMV replication.

Cyclophilin acts as a ribosome biogenesis factor by chaperoning the ribosomal protein (PlRPS15) in filamentous fungi.

The rapid transport of ribosomal proteins (RPs) into the nucleus and their efficient assembly into pre-ribosomal particles are prerequisites for ribosome biogenesis. Proteins that act as dedicated chaperones for RPs to maintain their stability and facilitate their assembly have not been identified in filamentous fungi. PlCYP5 is a nuclear cyclophilin in the nematophagous fungus Purpureocillium lilacinum, whose expression is up-regulated during abiotic stress and nematode egg-parasitism. Here, we found that PlCYP5 co-translationally interacted with the unassembled small ribosomal subunit protein, PlRPS15 (uS19). PlRPS15 contained an eukaryote-specific N-terminal extension that mediated the interaction with PlCYP5. PlCYP5 increased the solubility of PlRPS15 independent of its catalytic peptide-prolyl isomerase function and supported the integration of PlRPS15 into pre-ribosomes. Consistently, the phenotypes of the PlCYP5 loss-of-function mutant were similar to those of the PlRPS15 knockdown mutant (e.g. growth and ribosome biogenesis defects). PlCYP5 homologs in Arabidopsis thaliana, Homo sapiens, Schizosaccharomyces pombe, Sclerotinia sclerotiorum, Botrytis cinerea and Metarhizium anisopliae were identified. Notably, PlCYP5-PlRPS15 homologs from three filamentous fungi interacted with each other but not those from other species. In summary, our data disclosed a unique dedicated chaperone system for RPs by cyclophilin in filamentous fungi.

Plastome variation and phylogeny of Taxillus (Loranthaceae).

Several molecular phylogenetic studies of the mistletoe family Loranthaceae have been published such that now the general pattern of relationships among the genera and their biogeographic histories are understood. Less is known about species relationships in the larger (> 10 species) genera. This study examines the taxonomically difficult genus Taxillus composed of 35-40 Asian species. The goal was to explore the genetic diversity present in Taxillus plastomes, locate genetically variable hotspots, and test these for their utility as potential DNA barcodes. Using genome skimming, complete plastomes, as well as nuclear and mitochondrial rDNA sequences, were newly generated for eight species. The plastome sequences were used in conjunction with seven publicly available Taxillus sequences and three sequences of Scurrula, a close generic relative. The Taxillus plastomes ranged from 121 to 123 kbp and encoded 90-93 plastid genes. In addition to all of the NADH dehydrogenase complex genes, four ribosomal genes, infA and four intron-containing tRNA genes were lost or pseudogenized in all of the Taxillus and Scurrula plastomes. The topologies of the plastome, mitochondrial rDNA and nuclear rDNA trees were generally congruent, though with discordance at the position of T. chinensis. Several variable regions in the plastomes were identified that have sufficient numbers of parsimony informative sites as to recover the major clades seen in the complete plastome tree. Instead of generating complete plastome sequences, our study showed that accD alone or the concatenation of accD and rbcL can be used in future studies to facilitate identification of Taxillus samples and to generate a molecular phylogeny with robust sampling within the genus.

Pathogenic variants in MRPL44 cause infantile cardiomyopathy due to a mitochondrial translation defect.

Cardiac dysfunction is a common phenotypic manifestation of primary mitochondrial disease with multiple nuclear and mitochondrial DNA pathogenic variants as a cause, including disorders of mitochondrial translation. To date, five patients have been described with pathogenic variants in MRPL44, encoding the ml44 protein which is part of the large subunit of the mitochondrial ribosome (mitoribosome). Three presented as infants with hypertrophic cardiomyopathy, mild lactic acidosis, and easy fatigue and muscle weakness, whereas two presented in adolescence with myopathy and neurological symptoms. We describe two infants who presented with cardiomyopathy from the neonatal period, failure to thrive, hypoglycemia and in one infant lactic acidosis. A decompensation of the cardiac function in the first year resulted in demise. Exome sequencing identified compound heterozygous variants in the MRPL44 gene including the known pathogenic variant c.467 T > G and two novel pathogenic variants. We document a combined respiratory chain enzyme deficiency with emphasis on complex I and IV, affecting heart muscle tissue more than skeletal muscle or fibroblasts. We show this to be caused by reduced mitochondrial DNA encoded protein synthesis affecting all subunits, and resulting in dysfunction of complex I and IV assembly. The degree of oxidative phosphorylation dysfunction correlated with the impairment of mitochondrial protein synthesis due to different pathogenic variants. These functional studies allow for improved understanding of the pathogenesis of MRPL44-associated mitochondrial disorder.

Anomalous Phylogenetic Behavior of Ribosomal Proteins in Metagenome-Assembled Asgard Archaea.

Metagenomic studies permit the exploration of microbial diversity in a defined habitat, and binning procedures enable phylogenomic analyses, taxon description, and even phenotypic characterizations in the absence of morphological evidence. Such lineages include asgard archaea, which were initially reported to represent archaea with eukaryotic cell complexity, although the first images of such an archaeon show simple cells with prokaryotic characteristics. However, these metagenome-assembled genomes (MAGs) might suffer from data quality problems not encountered in sequences from cultured organisms due to two common analytical procedures of bioinformatics: assembly of metagenomic sequences and binning of assembled sequences on the basis of innate sequence properties and abundance across samples. Consequently, genomic sequences of distantly related taxa, or domains, can in principle be assigned to the same MAG and result in chimeric sequences. The impacts of low-quality or chimeric MAGs on phylogenomic and metabolic prediction remain unknown. Debates that asgard archaeal data are contaminated with eukaryotic sequences are overshadowed by the lack of evidence indicating that individual asgard MAGs stem from the same chromosome. Here, we show that universal proteins including ribosomal proteins of asgard archaeal MAGs fail to meet the basic phylogenetic criterion fulfilled by genome sequences of cultured archaea investigated to date: These proteins do not share common evolutionary histories to the same extent as pure culture genomes do, pointing to a chimeric nature of asgard archaeal MAGs. Our analysis suggests that some asgard archaeal MAGs represent unnatural constructs, genome-like patchworks of genes resulting from assembly and/or the binning process.

The evolving role of ribosomes in the regulation of protein synthesis.

Maintenance of the cellular homeostasis is firmly linked with protein synthesis. Therefore, it is tightly controlled at multiple levels. An advancement in quantitative techniques, mainly over the last decade, shed new light on the regulation of protein production, which pointed the ribosome as a new player. Ribosomes are macromolecular machines that synthesize polypeptide chains using mRNA as a template. The enormous complexity of ribosomes provides many possibilities of changes in their composition and consecutively in their target specificity. However, it is not clear how this specialization is enforced by the cell and which stimuli provoke that diversity. This review presents an overview of currently available knowledge about ribosome heterogeneity, focusing on changes in protein composition, and their role in the control of translation specificity. Importantly, besides the potential advantage of ribosome-mediated regulation of protein synthesis, its failure can play a crucial role in disease development.

The roles of vicariance and dispersal in the differentiation of two species of the Rhinella marina species complex.

The high levels of Neotropical biodiversity are commonly associated with the intense Neogene-Quaternary geological events and climate dynamics. Here, we investigate the evolutionary history of two species of Neotropical closely related amphibians (R. horribilis and R. marina). We combine published data with new mitochondrial DNA sequences and multiple nuclear markers, including 12 microsatellites. The phylogenetic analyses showed support for grouping the samples in two main clades; R. horribilis (Central America and Mexico) and R. marina (South America east of the Andes). However, the phylogenetic inferences also show an evident mito-nuclear discordance. We use Approximate Bayesian Computation (ABC) to test the role of different events in the diversification between the two groups recovered. We found that both species were affected primarily by a recent Pleistocene divergence, which was similar to the divergence estimate revealed by the Isolation-with-Migration model, under persistent bidirectional gene flow through time. We provide the first evidence that R. horribilis is differentiated from the South American R. marina at the nuclear level supporting the taxonomic status of R. horribilis, which has been controversial for more than a century.

Metagenomes from Coastal Marine Sediments Give Insights into the Ecological Role and Cellular Features of Loki- and Thorarchaeota.

The genomes of Asgard Archaea, a novel archaeal proposed superphylum, share an enriched repertoire of eukaryotic signature genes and thus promise to provide insights into early eukaryote evolution. However, the distribution, metabolisms, cellular structures, and ecology of the members within this superphylum are not well understood. Here we provide a meta-analysis of the environmental distribution of the Asgard archaea, based on available 16S rRNA gene sequences. Metagenome sequencing of samples from a salt-crusted lagoon on the Baja California Peninsula of Mexico allowed the assembly of a new Thorarchaeota and three Lokiarchaeota genomes. Comparative analyses of all known Lokiarchaeota and Thorarchaeota genomes revealed overlapping genome content, including central carbon metabolism. Members of both groups contained putative reductive dehalogenase genes, suggesting that these organisms might be able to metabolize halogenated organic compounds. Unlike the first report on Lokiarchaeota, we identified genes encoding glycerol-1-phosphate dehydrogenase in all Loki- and Thorarchaeota genomes, suggesting that these organisms are able to synthesize bona fide archaeal lipids with their characteristic glycerol stereochemistry.IMPORTANCE Microorganisms of the superphylum Asgard Archaea are considered to be the closest living prokaryotic relatives of eukaryotes (including plants and animals) and thus promise to give insights into the early evolution of more complex life forms. However, very little is known about their biology as none of the organisms has yet been cultivated in the laboratory. Here we report on the ecological distribution of Asgard Archaea and on four newly sequenced genomes of the Lokiarchaeota and Thorarchaeota lineages that give insight into possible metabolic features that might eventually help to identify these enigmatic groups of archaea in the environment and to culture them.

Exploring intrinsically disordered proteins in Chlamydomonas reinhardtii.

The content of intrinsically disordered protein (IDP) is related to organism complexity, evolution, and regulation. In the Plantae, despite their high complexity, experimental investigation of IDP content is lacking. We identified by mass spectrometry 682 heat-resistant proteins from the green alga, Chlamydomonas reinhardtii. Using a phosphoproteome database, we found that 331 of these proteins are targets of phosphorylation. We analyzed the flexibility propensity of the heat-resistant proteins and their specific features as well as those of predicted IDPs from the same organism. Their mean percentage of disorder was about 20%. Most of the IDPs (~70%) were addressed to other compartments than mitochondrion and chloroplast. Their amino acid composition was biased compared to other classic IDPs. Their molecular functions were diverse; the predominant ones were nucleic acid binding and unfolded protein binding and the less abundant one was catalytic activity. The most represented proteins were ribosomal proteins, proteins associated to flagella, chaperones and histones. We also found CP12, the only experimental IDP from C. reinhardtii that is referenced in disordered protein database. This is the first experimental investigation of IDPs in C. reinhardtii that also combines in silico analysis.

RiboDB Database: A Comprehensive Resource for Prokaryotic Systematics.

Ribosomal proteins (r-proteins) are increasingly used as an alternative to ribosomal rRNA for prokaryotic systematics. However, their routine use is difficult because r-proteins are often not or wrongly annotated in complete genome sequences, and there is currently no dedicated exhaustive database of r-proteins. RiboDB aims at fulfilling this gap. This weekly updated comprehensive database allows the fast and easy retrieval of r-protein sequences from publicly available complete prokaryotic genome sequences. The current version of RiboDB contains 90 r-proteins from 3,750 prokaryotic complete genomes encompassing 38 phyla/major classes and 1,759 different species. RiboDB is accessible at http://ribodb.univ-lyon1.fr and through ACNUC interfaces.

A ribosomal protein AgRPS3aE from halophilic Aspergillus glaucus confers salt tolerance in heterologous organisms.

High salt in soils is one of the abiotic stresses that significantly reduces crop yield, although saline lands are considered potential resources arable for agriculture. Currently, genetic engineering for enhancing salt tolerance is being tested as an efficient and viable strategy for crop improvement. We previously characterized a large subunit of the ribosomal protein RPL44, which is involved in osmotic stress in the extremely halophilic fungus Aspergillus glaucus. Here, we screened another ribosomal protein (AgRPS3aE) that also produced high-salt tolerance in yeast. Bioinformatics analysis indicated that AgRPS3aE encodes a 29.2 kDa small subunit of a ribosomal protein belonging to the RPS3Ae family in eukaryotes. To further confirm its protective function against salinity, we expressed AgRPS3aE in three heterologous systems, the filamentous fungus Magnaporthe oryzae and two model plants Arabidopsis and tobacco. Overexpression of AgRPS3aE in all tested transformants significantly alleviated stress symptoms compared with controls, suggesting that AgRPS3aE functions not only in fungi but also in plants. Considering that ribosomal proteins are housekeeping components in organisms from prokaryotes to eukaryotes, we propose that AgRPS3aE is one of the optimal genes for improving high-salt tolerance in crops.

Comparison of environmental and isolate Sulfobacillus genomes reveals diverse carbon, sulfur, nitrogen, and hydrogen metabolisms.

BACKGROUND: Bacteria of the genus Sulfobacillus are found worldwide as members of microbial communities that accelerate sulfide mineral dissolution in acid mine drainage environments (AMD), acid-rock drainage environments (ARD), as well as in industrial bioleaching operations. Despite their frequent identification in these environments, their role in biogeochemical cycling is poorly understood. RESULTS: Here we report draft genomes of five species of the Sulfobacillus genus (AMDSBA1-5) reconstructed by cultivation-independent sequencing of biofilms sampled from the Richmond Mine (Iron Mountain, CA). Three of these species (AMDSBA2, AMDSBA3, and AMDSBA4) have no cultured representatives while AMDSBA1 is a strain of S. benefaciens, and AMDSBA5 a strain of S. thermosulfidooxidans. We analyzed the diversity of energy conservation and central carbon metabolisms for these genomes and previously published Sulfobacillus genomes. Pathways of sulfur oxidation vary considerably across the genus, including the number and type of subunits of putative heterodisulfide reductase complexes likely involved in sulfur oxidation. The number and type of nickel-iron hydrogenase proteins varied across the genus, as does the presence of different central carbon pathways. Only the AMDSBA3 genome encodes a dissimilatory nitrate reducatase and only the AMDSBA5 and S. thermosulfidooxidans genomes encode assimilatory nitrate reductases. Within the genus, AMDSBA4 is unusual in that its electron transport chain includes a cytochrome bc type complex, a unique cytochrome c oxidase, and two distinct succinate dehydrogenase complexes. CONCLUSIONS: Overall, the results significantly expand our understanding of carbon, sulfur, nitrogen, and hydrogen metabolism within the Sulfobacillus genus.

A new system for naming ribosomal proteins.

A system for naming ribosomal proteins is described that the authors intend to use in the future. They urge others to adopt it. The objective is to eliminate the confusion caused by the assignment of identical names to ribosomal proteins from different species that are unrelated in structure and function. In the system proposed here, homologous ribosomal proteins are assigned the same name, regardless of species. It is designed so that new names are similar enough to old names to be easily recognized, but are written in a format that unambiguously identifies them as 'new system' names.

RPS8--a new informative DNA marker for phylogeny of Babesia and Theileria parasites in China.

Piroplasmosis is a serious debilitating and sometimes fatal disease. Phylogenetic relationships within piroplasmida are complex and remain unclear. We compared the intron-exon structure and DNA sequences of the RPS8 gene from Babesia and Theileria spp. isolates in China. Similar to 18S rDNA, the 40S ribosomal protein S8 gene, RPS8, including both coding and non-coding regions is a useful and novel genetic marker for defining species boundaries and for inferring phylogenies because it tends to have little intra-specific variation but considerable inter-specific difference. However, more samples are needed to verify the usefulness of the RPS8 (coding and non-coding regions) gene as a marker for the phylogenetic position and detection of most Babesia and Theileria species, particularly for some closely related species.

Ribosomal proteins as biomarkers for bacterial identification by mass spectrometry in the clinical microbiology laboratory.

Whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid method for identification of microorganisms that is increasingly used in microbiology laboratories. This identification is based on the comparison of the tested isolate mass spectrum with reference databases. Using Neisseria meningitidis as a model organism, we showed that in one of the available databases, the Andromas database, 10 of the 13 species-specific biomarkers correspond to ribosomal proteins. Remarkably, one biomarker, ribosomal protein L32, was subject to inter-strain variability. The analysis of the ribosomal protein patterns of 100 isolates for which whole genome sequences were available, confirmed the presence of inter-strain variability in the molecular weight of 29 ribosomal proteins, thus establishing a correlation between the sequence type (ST) and/or clonal complex (CC) of each strain and its ribosomal protein pattern. Since the molecular weight of three of the variable ribosomal proteins (L30, L31 and L32) was included in the spectral window observed by MALDI-TOF MS in clinical microbiology, i.e., 3640-12000 m/z, we were able by analyzing the molecular weight of these three ribosomal proteins to classify each strain in one of six subgroups, each of these subgroups corresponding to specific STs and/or CCs. Their detection by MALDI-TOF allows therefore a quick typing of N. meningitidis isolates.

The effects of model choice and mitigating bias on the ribosomal tree of life.

Deep-level relationships within Bacteria, Archaea, and Eukarya as well as the relationships of these three domains to each other require resolution. The ribosomal machinery, universal to all cellular life, represents a protein repertoire resistant to horizontal gene transfer, which provides a largely congruent signal necessary for reconstructing a tree suitable as a backbone for life's reticulate history. Here, we generate a ribosomal tree of life from a robust taxonomic sampling of Bacteria, Archaea, and Eukarya to elucidate deep-level intra-domain and inter-domain relationships. Lack of phylogenetic information and systematic errors caused by inadequate models (that cannot account for substitution rate or compositional heterogeneities) or improper model selection compound conflicting phylogenetic signals from HGT and/or paralogy. Thus, we tested several models of varying sophistication on three different datasets, performed removal of fast-evolving or long-branched Archaea and Eukarya, and employed three different strategies to remove compositional heterogeneity to examine their effects on the topological outcome. Our results support a two-domain topology for the tree of life, where Eukarya emerges from within Archaea as sister to a Korarchaeota/Thaumarchaeota (KT) or Crenarchaeota/KT clade for all models under all or at least one of the strategies employed. Taxonomic manipulation allows single-matrix and certain mixture models to vacillate between two-domain and three-domain phylogenies. We find that models vary in their ability to resolve different areas of the tree of life, which does not necessarily correlate with model complexity. For example, both single-matrix and some mixture models recover monophyletic Crenarchaeota and Euryarchaeota archaeal phyla. In contrast, the most sophisticated model recovers a paraphyletic Euryarchaeota but detects two large clades that comprise the Bacteria, which were recovered separately but never together in the other models. Overall, models recovered consistent topologies despite dataset modifications due to the removal of compositional bias, which reflects either ineffective bias reduction or robust datasets that allow models to overcome reconstruction artifacts. We recommend a comparative approach for evolutionary models to identify model weaknesses as well as consensus relationships.

Promiscuous behaviour of archaeal ribosomal proteins: implications for eukaryotic ribosome evolution.

In all living cells, protein synthesis occurs on ribonucleoprotein particles called ribosomes. Molecular models have been reported for complete bacterial 70S and eukaryotic 80S ribosomes; however, only molecular models of large 50S subunits have been reported for archaea. Here, we present a complete molecular model for the Pyrococcus furiosus 70S ribosome based on a 6.6 Å cryo-electron microscopy map. Moreover, we have determined cryo-electron microscopy reconstructions of the Euryarchaeota Methanococcus igneus and Thermococcus kodakaraensis 70S ribosomes and Crenarchaeota Staphylothermus marinus 50S subunit. Examination of these structures reveals a surprising promiscuous behavior of archaeal ribosomal proteins: We observe intersubunit promiscuity of S24e and L8e (L7ae), the latter binding to the head of the small subunit, analogous to S12e in eukaryotes. Moreover, L8e and L14e exhibit intrasubunit promiscuity, being present in two copies per archaeal 50S subunit, with the additional binding site of L14e analogous to the related eukaryotic r-protein L27e. Collectively, these findings suggest insights into the evolution of eukaryotic ribosomal proteins through increased copy number and binding site promiscuity.

Characterization of the ribosome biogenesis landscape in E. coli using quantitative mass spectrometry.

The ribosome is an essential and highly complex biological system in all living cells. A large body of literature on the assembly of the ribosome in vitro is available, but a clear picture of this process inside the cell has yet to emerge. Here, we directly characterized in vivo ribosome assembly intermediates and associated assembly factors from wild-type Escherichia coli cells using a general quantitative mass spectrometry (qMS) approach. The presence of distinct populations of ribosome assembly intermediates was verified using an in vivo stable isotope pulse-labeling approach, and their exact ribosomal protein contents were characterized against an isotopically labeled standard. The model-free clustering analysis of the resultant protein levels for the different ribosomal particles produced four 30S assembly groups that correlate very well with previous in vitro assembly studies of the small ribosomal subunit and six 50S assembly groups that clearly define an in vivo assembly landscape for the larger ribosomal subunit. In addition, de novo proteomics identified a total of 21 known and potentially new ribosome assembly factors co-localized with various ribosomal particles. These results represent new in vivo assembly maps of the E. coli 30S and 50S subunits, and the general qMS approach should prove to be a solid platform for future studies of ribosome biogenesis across a host of model organisms.

Genetic characterization and barcoding of taxa in the genus Wolffia Horkel ex Schleid. (Lemnaceae) as revealed by two plastidic markers and amplified fragment length polymorphism (AFLP).

The genus Wolffia of the duckweed family (Lemnaceae) contains the smallest flowering plants. Presently, 11 species are recognized and categorized mainly on the basis of morphology. Because of extreme reduction of structure of all species, molecular methods are especially required for barcoding and identification of species and clones of this genus. We applied AFLP combined with Bayesian analysis of population structure to 66 clones covering all 11 species. Nine clusters were identified: (1) W. angusta and W. microscopica (only one clone), (2) W. arrhiza, (3) W. cylindracea (except one clone that might be a transition form), (4) W. australiana, (5) W. globosa, (6) W. globosa, W. neglecta, and W. borealis, (7) W. brasiliensis, and W. columbiana, (8) W. columbiana, (9) W. elongata. Furthermore, we investigated the sequences of plastidic regions rps16 (54 clones) and rpl16 (55 clones), and identified the following species: W. angusta, W. australiana, W. brasiliensis, W. cylindracea, W. elongata, W. microscopica, and W. neglecta. Wolffia globosa has been separated into two groups by both methods. One group which consists only of clones from North America and East Asia was labelled here "typical W. globosa". The other group of W. globosa, termed operationally "W. neglecta", contains also clones of W. neglecta and shows high similarity to W. borealis. None of the methods recognized W. borealis as a distinct species. Although each clone could be characterized individually by AFLP and plastidic sequences, and most species could be bar-coded, the presently available data are not sufficient to identify all taxa of Wolffia.

Selective blockade of trypanosomatid protein synthesis by a recombinant antibody anti-Trypanosoma cruzi P2ß protein.

The ribosomal P proteins are located on the stalk of the ribosomal large subunit and play a critical role during the elongation step of protein synthesis. The single chain recombinant antibody C5 (scFv C5) directed against the C-terminal region of the Trypanosoma cruzi P2ß protein (TcP2ß) recognizes the conserved C-terminal end of all T. cruzi ribosomal P proteins. Although this region is highly conserved among different species, surface plasmon resonance analysis showed that the scFv C5 possesses very low affinity for the corresponding mammalian epitope, despite having only one single amino-acid change. Crystallographic analysis, in silico modelization and NMR assays support the analysis, increasing our understanding on the structural basis of epitope specificity. In vitro protein synthesis experiments showed that scFv C5 was able to specifically block translation by T. cruzi and Crithidia fasciculata ribosomes, but virtually had no effect on Rattus norvegicus ribosomes. Therefore, we used the scFv C5 coding sequence to make inducible intrabodies in Trypanosoma brucei. Transgenic parasites showed a strong decrease in their growth rate after induction. These results strengthen the importance of the P protein C terminal regions for ribosomal translation activity and suggest that trypanosomatid ribosomal P proteins could be a possible target for selective therapeutic agents that could be derived from structural analysis of the scFv C5 antibody paratope.