RESUMO
Selenium (Se) is a vital trace element, essential for growth and other biological functions in fish. Its significance lies in its role as a fundamental component of selenoproteins, which are crucial for optimal functioning of the organism. The inclusion of Se in the diets of farmed animals, including fish, has proved invaluable in mitigating the challenges arising from elemental deficiencies experienced in captivity conditions due to limitations in the content of fishmeal. Supplementing diets with Se enhances physiological responses, particularly mitigates the effects of the continuous presence of environmental stress factors. Organic Se has been shown to have higher absorption rates and a greater impact on bioavailability and overall health than inorganic forms. A characteristic feature of yeasts is their rapid proliferation and growth, marked by efficient mineral assimilation. Most of the selenized yeasts currently available in the market, and used predominantly in animal production and aquaculture, are based on Saccharomyces cerevisiae, which contains selenomethionine (Se-Met). The object of this review is to highlight the importance of selenized yeasts. In addition, it presents metabolic and productive aspects of other yeast genera that are important potential sources of organic selenium. Some yeast strains discussed produce metabolites of interest such as lipids, pigments, and amino acids, which could have applications in aquaculture and further enrich their usefulness.
Assuntos
Ração Animal , Peixes , Selênio , Animais , Ração Animal/análise , Peixes/microbiologia , Peixes/metabolismo , Selênio/metabolismo , Leveduras/metabolismo , Dieta/veterinária , Suplementos NutricionaisRESUMO
There is large diversity among glutathione peroxidase (GPx) enzymes regarding their function, structure, presence of the highly reactive selenocysteine (SeCys) residue, substrate usage, and reducing agent preference. Moreover, most vertebrate GPxs are very distinct from non-animal GPxs, and it is still unclear if they came from a common GPx ancestor. In this study, we aimed to unveil how GPx evolved throughout different phyla. Based on our phylogenetic trees and sequence analyses, we propose that all GPx encoding genes share a monomeric common ancestor and that the SeCys amino acid was incorporated early in the evolution of the metazoan kingdom. In addition, classical GPx and the cysteine-exclusive GPx07 have been present since non-bilaterian animals, but they seem to have been lost throughout evolution in different phyla. Therefore, the birth-and-death of GPx family members (like in other oxidoreductase families) seems to be an ongoing process, occurring independently across different kingdoms and phyla.
RESUMO
People with obesity are often dyslipidemic and prescribed statins to prevent cardiovascular events. A common side effect of statin use is myopathy. This could potentially be caused by the reduction of selenoproteins that curb oxidative stress, in turn, affecting creatine metabolism. We determined if statins regulate hepatic and muscular selenoprotein expression, oxidative stress and creatine metabolism. Mice lacking selenocysteine lyase (Scly KO), a selenium-provider enzyme for selenoprotein synthesis, were fed a high-fat, Se-supplemented diet and treated with simvastatin. Statin improved creatine metabolism in females and oxidative responses in both sexes. Male Scly KO mice were heavier than females after statin treatment. Hepatic selenoproteins were unaffected by statin and genotype in females. Statin upregulated muscular Gpx1 in females but not males, while Scly loss downregulated muscular Gpx1 in males and Selenon in females. Osgin1 was reduced in statin-treated Scly KO males after AmpliSeq analysis. These results refine our understanding of the sex-dependent role of selenium in statin responses.
Assuntos
Fígado/metabolismo , Liases/genética , Músculo Esquelético/metabolismo , Obesidade/tratamento farmacológico , Selenoproteínas/metabolismo , Sinvastatina/administração & dosagem , Animais , Creatinina/metabolismo , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Feminino , Glutationa Peroxidase/metabolismo , Fígado/efeitos dos fármacos , Masculino , Camundongos , Camundongos Knockout , Camundongos Obesos , Músculo Esquelético/efeitos dos fármacos , Obesidade/induzido quimicamente , Obesidade/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Selênio , Caracteres Sexuais , Sinvastatina/farmacologia , Glutationa Peroxidase GPX1RESUMO
BACKGROUND: The amino acid selenocysteine (Sec) is an integral part of selenoproteins, a class of proteins mostly involved in strong redox reactions. The enzyme Sec lyase (SCLY) decomposes Sec into selenide allowing for the recycling of the selenium (Se) atom via the selenoprotein synthesis machinery. We previously demonstrated that disruption of the Scly gene (Scly KO) in mice leads to the development of obesity and metabolic syndrome, with effects on glucose homeostasis, worsened by Se deficiency or a high-fat diet, and exacerbated in male mice. Our objective was to determine whether Se supplementation could ameliorate obesity and restore glucose homeostasis in the Scly KO mice. METHODS: Three-weeks old male and female Scly KO mice were fed in separate experiments a diet containing 45 % kcal fat and either sodium selenite or a mixture of sodium selenite and selenomethionine (selenite/SeMet) at moderate (0.25â¯ppm) or high (0.5-1â¯ppm) levels for 9 weeks, and assessed for metabolic parameters, oxidative stress and expression of selenoproteins. RESULTS: Se supplementation was unable to prevent obesity and elevated epididymal white adipose tissue weights in male Scly KO mice. Serum glutathione peroxidase activity in Scly KO mice was unchanged regardless of sex or dietary Se intake; however, supplementation with a mixture of selenite/SeMet improved oxidative stress biomarkers in the male Scly KO mice. CONCLUSION: These results unveil sex- and selenocompound-specific regulation of energy metabolism after the loss of Scly, pointing to a role of this enzyme in the control of whole-body energy metabolism regardless of Se levels.
Assuntos
Liases/metabolismo , Obesidade/metabolismo , Selênio/uso terapêutico , Animais , Biomarcadores/metabolismo , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Liases/genética , Masculino , Síndrome Metabólica/induzido quimicamente , Síndrome Metabólica/metabolismo , Camundongos , Camundongos Knockout , Obesidade/induzido quimicamente , Estresse Oxidativo/efeitos dos fármacos , Ácido Selenioso/uso terapêuticoRESUMO
Selenium (Se) is an essential micronutrient for the majority of living organisms, and it has been identified as selenocysteine in the active site of several selenoproteins such as glutathione peroxidase, thioredoxin reductase, and deiodinases. Se deficiency in humans is associated with viral infections, thyroid dysfunction, different types of cancer, and aging. In several European countries as well as in Argentina, Se intake is below the recommended dietary Intake (RDI). Some lactic acid bacteria (LAB) can accumulate and bio-transform selenite (toxic) into Se-nanoparticles (SeNPs) and Se-amino acids (non-toxic). The microbial growth, Se metabolite distribution, and the glutathione reductase (involved in selenite reduction) activity of Se-enriched LAB were studied in this work. The ninety-six assayed strains, belonging to the genera Lactococcus, Weissella, Leuconostoc, Lactobacillus, Enterococcus, and Fructobacillus could grow in the presence of 5 ppm sodium selenite. From the total, eight strains could remove more than 80% of the added Se from the culture medium. These bacteria accumulated intracellularly between 1.2 and 2.5 ppm of the added Se, from which F. tropaeoli CRL 2034 contained the highest intracellular amount. These strains produced only the seleno-amino acid SeCys as observed by LC-ICP-MS and confirmed by LC-ESI-MS/MS. The intracellular SeCys concentrations were between 0.015 and 0.880 ppm; Lb. brevis CRL 2051 (0.873 ppm), Lb. plantarum CRL 2030 (0.867 ppm), and F. tropaeoli CRL 2034 (0.625 ppm) were the strains that showed the highest concentrations. Glutathione reductase activity values were higher when the strains were grown in the presence of Se except for the F. tropaeoli CRL 2034 strain, which showed an opposite behavior. The cellular morphology of the strains was not affected by the presence of Se in the culture medium; interestingly, all the strains were able to form spherical SeNPs as determined by transmission electron microscopy (TEM). Only two Enterococcus strains produced the volatile Se compounds dimethyl-diselenide identified by GC-MS. Our results show that Lb. brevis CRL 2051, Lb. plantarum CRL 2030, and F. tropaeoli CRL 2034 could be used for the development of nutraceuticals or as starter cultures for the bio-enrichment of fermented fruit beverages with SeCys and SeNPs.
RESUMO
tRNA synthetases are responsible for decoding the molecular information, from codons to amino acids. Seryl-tRNA synthetase (SerRS), besides the five isoacceptors of tRNASer, recognizes tRNA[Ser]Sec for the incorporation of selenocysteine (Sec, U) into selenoproteins. The selenocysteine synthesis pathway is known and is dependent on several protein-protein and protein-RNA interactions. Those interactions are not fully described, in particular, involving tRNA[Ser]Sec and SerRS. Here we describe the molecular interactions between the Escherichia coli Seryl-tRNA synthetase (EcSerRS) and tRNA[Ser]Sec in order to determine their specificity, selectivity and binding order, leading to tRNA aminoacylation. The dissociation constant of EcSerRS and tRNA[Ser]Sec was determined as (126 ± 20) nM. We also demonstrate that EcSerRS binds initially to tRNA[Ser]Sec in the presence of ATP for further recognition by E. coli selenocysteine synthetase (EcSelA) for Ser to Sec conversion. The proposed studies clarify the mechanism of tRNA[Ser]Sec incorporation in Bacteria as well as of other domains of life.
Assuntos
Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , RNA de Transferência Aminoácido-Específico/metabolismo , RNA de Transferência de Cisteína/metabolismo , Serina-tRNA Ligase/metabolismo , Transferases/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Escherichia coli/genética , Cinética , Modelos Moleculares , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , RNA de Transferência Aminoácido-Específico/genética , RNA de Transferência de Cisteína/genética , Serina-tRNA Ligase/genética , Termodinâmica , Aminoacilação de RNA de Transferência/genética , Transferases/genéticaRESUMO
A combined organocatalytic and multicomponent synthetic approach was designed for the preparation of selenium-based peptoids and peptide-peptoid conjugates. This single-step synthetic protocol comprises the organocatalytic asymmetric insertion of phenylselenium in the aldehyde moiety followed by the Ugi four-component reaction which results in obtaining the desired compounds in good-to-moderate yields and with good-to-excellent levels of stereoselectivity.
Assuntos
Técnicas de Química Sintética , Fenômenos de Química Orgânica , Peptoides/síntese química , Selênio , Espectroscopia de Ressonância MagnéticaRESUMO
Selenium (Se) is an essential trace element for several organisms and is mostly present in proteins as L-selenocysteine (Sec or U). Sec is synthesized on its L-seryl-tRNASec to produce Sec-tRNASec molecules by a dedicated selenocysteine synthesis machinery and incorporated into selenoproteins at specified in-frame UGA codons. UGA-Sec insertion is signaled by an mRNA stem-loop structure called the SElenoCysteine Insertion Sequence (SECIS). tRNASec transcription regulation and folding have been described showing its importance to Sec biosynthesis. Here, we discuss structural aspects of Sec-tRNASec and its role in Sec biosynthesis as well as Sec incorporation into selenoproteins. Defects in the Sec biosynthesis or incorporation pathway have been correlated with pathological conditions.
Assuntos
RNA de Transferência de Cisteína/genética , Selenocisteína/biossíntese , Animais , Códon de Terminação/química , Códon de Terminação/genética , Códon de Terminação/metabolismo , Humanos , Biossíntese de Proteínas , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Transferência de Cisteína/química , RNA de Transferência de Cisteína/metabolismo , Selenocisteína/genéticaRESUMO
The antagonism of mercury toxicity by selenium has been well documented. Mercury is a toxic metal, widespread in the environment. The main target organs (kidneys, lungs, or brain) of mercury vary depending on its chemical forms (inorganic or organic). Selenium is a semimetal essential to mammalian life as part of the amino acid selenocysteine, which is required to the synthesis of the selenoproteins. This chapter has the aim of disclosing the role of selenide or hydrogen selenide (Se-2 or HSe-) as central metabolite of selenium and as an important antidote of the electrophilic mercury forms (particularly, Hg2+ and MeHg). Emphasis will be centered on the neurotoxicity of electrophile forms of mercury and selenium. The controversial participation of electrophile mercury and selenium forms in the development of some neurodegenerative disease will be briefly presented. The potential pharmacological use of organoseleno compounds (Ebselen and diphenyl diselenide) in the treatment of mercury poisoning will be considered. The central role of thiol (-SH) and selenol (-SeH) groups as the generic targets of electrophile mercury forms and the need of new in silico tools to guide the future biological researches will be commented.
Assuntos
Encéfalo/metabolismo , Intoxicação do Sistema Nervoso por Mercúrio/metabolismo , Síndromes Neurotóxicas/etiologia , Selênio/intoxicação , Antídotos/uso terapêutico , Azóis/uso terapêutico , Derivados de Benzeno/uso terapêutico , Humanos , Isoindóis , Intoxicação por Mercúrio/tratamento farmacológico , Intoxicação por Mercúrio/metabolismo , Intoxicação do Sistema Nervoso por Mercúrio/tratamento farmacológico , Síndromes Neurotóxicas/tratamento farmacológico , Síndromes Neurotóxicas/metabolismo , Compostos Organosselênicos/uso terapêutico , Selenoproteínas/metabolismoRESUMO
OBJECTIVE: The free radical theory of aging suggests that cellular oxidative damage caused by free radicals is a leading cause of aging. In the present study, we examined the effects of a well-known anti-oxidant amino acid derivative, selenocysteine, in response to environmental stress and aging using Caenorhabditis elegans as a model system. METHOD: The response to oxidative stress induced by H2O2 or ultraviolet irradiation was compared between the untreated control and selenocysteine-treated groups. The effect of selenocysteine on lifespan and fertility was then determined. To examine the effect of selenocysteine on muscle aging, we monitored the change in motility with aging in both the untreated control and selenocysteine-treated groups. RESULTS: Dietary supplementation with selenocysteine significantly increased resistance to oxidative stress. Survival after ultraviolet irradiation was also increased by supplementation with selenocysteine. Treatment with selenocysteine confers a longevity phenotype without an accompanying reduction in fertility, which is frequently observed in lifespan-extending interventions as a trade-off in C. elegans. In addition, the age-related decline in motility was significantly delayed by supplementation of selenocysteine. CONCLUSION: These findings suggest that dietary supplementation of selenocysteine can modulate response to stressors and lead to lifespan extension, thus supporting the free radical theory of aging.
Assuntos
Animais , Envelhecimento/efeitos dos fármacos , Selenocisteína/farmacologia , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Antioxidantes/farmacologia , Reprodução/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Fatores de Tempo , Reprodutibilidade dos Testes , Fatores Etários , Caenorhabditis elegans/efeitos da radiação , Fertilidade/efeitos dos fármacos , Locomoção/efeitos dos fármacos , Longevidade/efeitos dos fármacosRESUMO
AIMS: New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with AuI-MPO, a novel gold inhibitor, together with inhibition assays were performed. RESULTS: AuI-MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer-monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys519 and Cys573 in the AuI-TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, CysâSer mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. INNOVATION: The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. CONCLUSIONS: The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys519 and Cys573 residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491-1504.
Assuntos
Echinococcus granulosus/enzimologia , Complexos Multienzimáticos/química , Complexos Multienzimáticos/metabolismo , NADH NADPH Oxirredutases/química , NADH NADPH Oxirredutases/metabolismo , Compostos Organoáuricos/farmacologia , Animais , Sítios de Ligação/efeitos dos fármacos , Cisteína/metabolismo , Echinococcus granulosus/química , Echinococcus granulosus/genética , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacocinética , Glutarredoxinas/metabolismo , Proteínas de Helminto/química , Proteínas de Helminto/genética , Proteínas de Helminto/metabolismo , Modelos Moleculares , Complexos Multienzimáticos/genética , Mutação , NADH NADPH Oxirredutases/genética , Compostos Organoáuricos/química , Ligação Proteica , Conformação ProteicaRESUMO
Selenoprotein T (SELENOT) is an endoplasmatic reticulum (ER)-associated redoxin that contains the amino acid selenocysteine (Sec, U) within a CXXU motif within a thioredoxin-like fold. Its precise function in multicellular organisms is not completely understood although it has been shown in mammals to be involved in Ca2+ homeostasis, antioxidant and neuroendocrine functions. Here, we use the model organism C. elegans to address SELENOT function in a whole organism throughout its life cycle. C. elegans possess two genes encoding SELENOT protein orthologues (SELT-1.1 and SELT-1.2), which lack Sec and contain the CXXC redox motif instead. Our results show that a SecâCys replacement and a gene duplication were two major evolutionary events that occurred in the nematode lineage. We find that worm SELT-1.1 localizes to the ER and is expressed in different cell types, including the nervous system. In contrast, SELT-1.2 exclusively localizes in the cytoplasm of the AWB neurons. We find that selt-1.1 and selt-1.2 single mutants as well as the double mutant are viable, but the selt-1.1 mutant is compromised under rotenone-induced oxidative stress. We demonstrate that selt-1.1, but not selt-1.2, is required for avoidance to the bacterial pathogens Serratia marcescens and Pseudomonas aeruginosa. Aversion to the noxious signal 2-nonanone is also significantly impaired in selt-1.1, but not in selt-1.2 mutant animals. Our results suggest that selt-1.1 would be a redox transducer required for nociception and optimal organismal fitness. The results highlight C. elegans as a valuable model organism to study SELENOT-dependent processes.
Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/imunologia , Retículo Endoplasmático/metabolismo , Neurônios/metabolismo , Infecções por Pseudomonas/imunologia , Pseudomonas aeruginosa/imunologia , Selenoproteínas/metabolismo , Infecções por Serratia/imunologia , Serratia marcescens/imunologia , Animais , Proteínas de Caenorhabditis elegans/genética , Células Cultivadas , Cisteína/genética , Duplicação Gênica , Imunidade Inata , Cetonas/administração & dosagem , Estágios do Ciclo de Vida , Mutação/genética , Nociceptividade , Estresse Oxidativo , Transporte Proteico , Selenoproteínas/genéticaRESUMO
The trace element selenium is found in polypeptides as selenocysteine, the 21(st) amino acid that is co-translationally inserted into proteins at a UGA codon. In proteins, selenocysteine usually plays a role as an efficient redox catalyst. Trypanosomatids previously examined harbor a full set of genes encoding the machinery needed for selenocysteine biosynthesis and incorporation into three selenoproteins: SelK, SelT and, the parasite-specific, Seltryp. We investigated the selenoproteome of kinetoplastid species in recently sequenced genomes and assessed the in vivo relevance of selenoproteins for African trypanosomes. Database mining revealed that SelK, SelT and Seltryp genes are present in most kinetoplastids, including the free-living species Bodo saltans, and Seltryp was lost in the subgenus Viannia from the New World Leishmania. Homology and sinteny with bacterial sulfur dioxygenases and sulfur transferases suggest a putative role for Seltryp in sulfur metabolism. A Trypanosoma brucei selenocysteine synthase (SepSecS) null-mutant, in which selenoprotein synthesis is abolished, displayed similar sensitivity to oxidative stress induced by a short-term exposure to high concentrations of methylglyoxal or H2O2 to that of the parental wild-type cell line. Importantly, the infectivity of the SepSecS knockout cell line was not impaired when tested in a mouse infection model and compensatory effects via up-regulation of proteins involved in thiol-redox metabolism were not observed. Collectively, our data show that selenoproteins are not required for survival of African trypanosomes in a mammalian host and exclude a role for selenoproteins in parasite antioxidant defense and/or virulence. On this basis, selenoproteins can be disregarded as drug target candidates.
Assuntos
Kinetoplastida/metabolismo , Proteínas de Protozoários/genética , Selenocisteína/metabolismo , Selenoproteínas/genética , Transferases/genética , Trypanosoma brucei brucei/metabolismo , Animais , Mineração de Dados , Bases de Dados Genéticas , Deleção de Genes , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita , Peróxido de Hidrogênio/farmacologia , Kinetoplastida/classificação , Kinetoplastida/efeitos dos fármacos , Kinetoplastida/crescimento & desenvolvimento , Camundongos , Filogenia , Proteoma/genética , Proteoma/metabolismo , Proteínas de Protozoários/metabolismo , Aldeído Pirúvico/farmacologia , Selenoproteínas/deficiência , Transferases/deficiência , Trypanosoma brucei brucei/classificação , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/crescimento & desenvolvimento , Tripanossomíase Africana/parasitologia , Tripanossomíase Africana/patologiaRESUMO
Selenocysteine (Sec) is encoded by an UGA codon with the help of a SECIS element present in selenoprotein mRNAs. SECIS-binding protein (SBP2/SCBP-2) mediates Sec insertion, but the roles of its domains and the impact of its deficiency on Sec insertion are not fully understood. We used Caenorhabditis elegans to examine SBP2 function since it possesses a single selenoprotein, thioredoxin reductase-1 (TRXR-1). All SBP2 described so far have an RNA-binding domain (RBD) and a Sec-incorporation domain (SID). Surprisingly, C. elegans SBP2 lacks SID and consists only of an RBD. An sbp2 deletion mutant strain ablated Sec incorporation demonstrating SBP2 essentiality for Sec incorporation. Further in silico analyses of nematode genomes revealed conservation of SBP2 lacking SID and maintenance of Sec incorporation linked to TRXR-1. Remarkably, parasitic plant nematodes lost the ability to incorporate Sec, but retained SecP43, a gene associated with Sec incorporation. Interestingly, both selenophosphate synthetase (SPS) genes are absent in plant parasitic nematodes, while only Cys-containing SPS2 is present in Sec-incorporating nematodes. Our results indicate that C. elegans and the nematode lineage provide key insights into Sec incorporation and the evolution of Sec utilization trait, selenoproteomes, selenoproteins, and Sec residues. Finally, our study provides evidence of noncanonical translation initiation in C. elegans, not previously known for this well-established animal model.
Assuntos
Adaptação Biológica/genética , Caenorhabditis elegans/metabolismo , Evolução Molecular , Inativação Gênica , Redes e Vias Metabólicas/genética , Selenocisteína/metabolismo , Sequência de Aminoácidos , Animais , Pareamento de Bases , Sequência de Bases , Caenorhabditis elegans/genética , Códon de Terminação , Dados de Sequência Molecular , Filogenia , RNA de Transferência/genética , RNA de Transferência/metabolismo , Selenocisteína/genética , Selenoproteínas/genéticaRESUMO
Selenophosphate synthetase (SPS) plays an indispensable role in selenium metabolism, being responsible for catalyzing the activation of selenide with adenosine 5'-triphosphate (ATP) to generate selenophosphate, the essential selenium donor for selenocysteine synthesis. Recombinant full-length Leishmania major SPS (LmSPS2) was recalcitrant to crystallization. Therefore, a limited proteolysis technique was used and a stable N-terminal truncated construct (ΔN-LmSPS2) yielded suitable crystals. The Trypanosoma brucei SPS orthologue (TbSPS2) was crystallized by the microbatch method using paraffin oil. X-ray diffraction data were collected to resolutions of 1.9 Å for ΔN-LmSPS2 and 3.4 Å for TbSPS2.