J.A. Black , B.C. Poulton , B. Gonzaga , A. Iskantar , D. Paape , L.R.O. Tosi. , R. McCulloch
{"title":"AUK3 is required for faithful nuclear segregation in the bloodstream form of Trypanosoma brucei","authors":"J.A. Black , B.C. Poulton , B. Gonzaga , A. Iskantar , D. Paape , L.R.O. Tosi. , R. McCulloch","doi":"10.1016/j.molbiopara.2024.111664","DOIUrl":"10.1016/j.molbiopara.2024.111664","url":null,"abstract":"<div><div>Eukaryotic chromosomes segregate faithfully prior to nuclear division to ensure genome stability. If segregation becomes defective, the chromosome copy number of the cell may alter leading to aneuploidy and/or polyploidy, both common hallmarks of cancers. In eukaryotes, aurora kinases regulate chromosome segregation during mitosis and meiosis, but their functions in the divergent, single-celled eukaryotic pathogen <em>Trypanosoma brucei</em> are less understood. Here, we focused on one of three aurora kinases in these parasites, TbAUK3, a homologue of the human aurora kinase AURKC, whose functions are primarily restricted to meiosis. We show that RNAi targeted depletion of TbAUK3 correlates with nuclear segregation defects, reduced proliferation, and decreased DNA synthesis, suggestive of a role for TbAUK3 during mitotic, not meiotic, chromosome segregation. Moreover, we uncover a putative role for TbAUK3 during the parasite's response to DNA damage since we show that depletion of TbAUK3 enhances DNA instability and sensitivity to genotoxic agents.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"261 ","pages":"Article 111664"},"PeriodicalIF":1.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142922074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mehdi Karamian , Esmat Alemzadeh , Ali Abedi , Soudabeh Eshaghi , Meghdad Abdollahpour-Alitappeh , Effat Alemzadeh , Motahareh Mahi-Birjand
{"title":"Glucantime and quercetin electrospun nanofiber membranes: Fabrication and their evaluation as dressing for cutaneous leishmaniasis","authors":"Mehdi Karamian , Esmat Alemzadeh , Ali Abedi , Soudabeh Eshaghi , Meghdad Abdollahpour-Alitappeh , Effat Alemzadeh , Motahareh Mahi-Birjand","doi":"10.1016/j.molbiopara.2024.111663","DOIUrl":"10.1016/j.molbiopara.2024.111663","url":null,"abstract":"<div><div>Cutaneous leishmaniasis is considered as one of the most concerns of the World Health Organization (WHO). The main objective of this study was to use polycaprolactone (PCL) nanofiber scaffolds in order to provide a topical drug delivery system capable of delivering glucantime (glu) and quercetin (qur) to cutaneous leishmaniasis wounds. First, PCL/glu/qur, PCL/glu, and PCL/qur nanofibers were prepared by an electrospinning method followed by characterization through scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). Subsequently, we investigated the release of the drugs from nano-scaffolds and anti-promastigote effects. Lastly, the effect of nanobandage was evaluated on 20 female inbred BALB/c mice infected with the parasite. The nanofibers were bead-free and uniform with an average diameter of 224 ± 25 nm and showed a sustained release. Results from <em>in vivo</em> experiments showed that the number of amastigotes and macrophages infected with the parasite and the infiltration of inflammatory cells in mice treated with PCL/qur and PCL/glu/qur nanofibers significantly decreased as compared with those treated with the PCL/glu and PCL nanofibers. Collectively, PCL/glu/qur and PCL/qur nanofibers have promising therapeutic effects in cutaneous leishmaniasis wound healing.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"261 ","pages":"Article 111663"},"PeriodicalIF":1.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142829417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Does Schistosoma mansoni trigger colorectal cancer?","authors":"Sidhant Jain","doi":"10.1016/j.molbiopara.2025.111672","DOIUrl":"10.1016/j.molbiopara.2025.111672","url":null,"abstract":"<div><div>In this work the relationship between <em>Schistosoma mansoni</em> (Sm) and the induction and progression of colorectal cancer (CRC) is examined. Various clinical studies reviewed here yield inconsistent results, with some reporting no association between Sm infection and CRC and others suggesting a probable to strong association. Here we propose a number of plausible mechanisms whereby Sm infection might contribute to CRC induction and/or progression. These factors are (1) chronic inflammation, (2) exposure to parasite linked antigens and genotoxic products, especially soluble egg antigens (SEAs) and (3) alteration of the intestinal microbiota. These factors probably predispose humans towards CRC and can help in CRC progression however only widespread epidemiological, clinical and pathological studies can firmly establish their role or a complete lack of it.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"262 ","pages":"Article 111672"},"PeriodicalIF":1.4,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143080471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Molecular and biochemical characterization of parasites protein phosphorylation: Emerging trends, challenges and opportunities.","authors":"Kayode K Ojo, Sumiti Vinayak","doi":"10.1016/j.molbiopara.2025.111675","DOIUrl":"https://doi.org/10.1016/j.molbiopara.2025.111675","url":null,"abstract":"","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":" ","pages":"111675"},"PeriodicalIF":1.4,"publicationDate":"2025-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143066474","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amal I. El-Refaiy , Nahed S. Amer , Amani Alhejely , Safa H. Qahl , Amira M. Shaban , Amro E. Mohamed , Amira A. Saleh , Abdelnaser A. Badawy , Mohammed A. El-Magd
{"title":"Impact of dandelion (Taraxacum officinale) leaf aqueous extract on immunological response of mice after Schistosoma mansoni infection","authors":"Amal I. El-Refaiy , Nahed S. Amer , Amani Alhejely , Safa H. Qahl , Amira M. Shaban , Amro E. Mohamed , Amira A. Saleh , Abdelnaser A. Badawy , Mohammed A. El-Magd","doi":"10.1016/j.molbiopara.2025.111673","DOIUrl":"10.1016/j.molbiopara.2025.111673","url":null,"abstract":"<div><div>This study investigated the effect of dandelion (<em>Taraxacum officinale</em>) leaf aqueous extract (DLE) on the immunological response of mice following infection with <em>Schistosoma mansoni</em>. Mice (in groups of 7) were first experimentally infected with <em>S. mansoni</em> and, 6 weeks later, were treated with praziquantel (PZQ) and/or DLE. Control mice were uninfected. In contrast to the untreated group, animals given PZQ and/or DLE exhibited an enhanced immunological response, as indicated by increased serum IFNγ, TNFα, IL4 and IL10 levels, increased numbers of CD4 + and CD25 + cells in blood and spleen and altered expression of apoptosis-related genes (low <em>Bax</em> and caspase3 and high <em>Bcl2</em>) in the spleen. DLE treatment had a significantly bigger impact in all these parameters compared with PZQ alone and combined DLE/PZQ treatment have the largest effect. While DLE treatment alone significantly decreased parasite burden, it did not improve upon the greater protective effect of PZQ, even when given in combination.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"262 ","pages":"Article 111673"},"PeriodicalIF":1.4,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143059182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cristian Vicson Gomes Pinheiro , Yasmim Mendes Rocha , João Pedro Viana Rodrigues , Gabriel Acácio de Moura , Juliana Ramos de Oliveira , Francisco Dantas Lourenço , Maria Jânia Teixeira , Valentina Nascimento Melo de Oliveira , Ronaldo Nascimento de Oliveira , Wildson Max Barbosa da Silva , Sara Ingrid Caetano Gomes Barbosa , Daniela Ribeiro Alves , Selene Maia de Morais , Roberto Nicolete
{"title":"In Silico and in vitro assessment of anti-leishmania infantum activity of a novel cyclohexyl-1,2,4-oxadiazole derivative","authors":"Cristian Vicson Gomes Pinheiro , Yasmim Mendes Rocha , João Pedro Viana Rodrigues , Gabriel Acácio de Moura , Juliana Ramos de Oliveira , Francisco Dantas Lourenço , Maria Jânia Teixeira , Valentina Nascimento Melo de Oliveira , Ronaldo Nascimento de Oliveira , Wildson Max Barbosa da Silva , Sara Ingrid Caetano Gomes Barbosa , Daniela Ribeiro Alves , Selene Maia de Morais , Roberto Nicolete","doi":"10.1016/j.molbiopara.2025.111674","DOIUrl":"10.1016/j.molbiopara.2025.111674","url":null,"abstract":"<div><div>Globally, an estimated 1 billion people reside in endemic areas, and over 12 million individuals are infected with leishmaniasis. Despite its prevalence, leishmaniasis continues to be a neglected disease, mainly affecting underdeveloped countries. In Brazil, the available treatments are pentavalent antimonials and amphotericin B, which are outdated, toxic, require prolonged parenteral administration and have limited efficacy. The heterocyclic ring oxadiazole has been documented in the literature to possess various biological activities, including leishmanicidal properties, thus positioning it as a potential candidate for further investigation. This study aims to evaluate the <em>in vitro</em> leishmanicidal activity of an oxadiazole compound (2i), explore its mechanism of action through enzymatic inhibition and molecular docking, assess its antioxidant activity, and conduct an <em>in silico</em> pharmacokinetic prediction. Pharmacokinetic predictions via ADME/TOX modeling revealed that the 2i molecule exhibits good intestinal absorption (92 %), is water-insoluble (-4 log.mol/L) and demonstrates high permeability in Caco-2 cells (1.35 log.Papp10–6cm/s), suggesting potential for oral administration. Metabolic studies indicated that oxadiazole 2i is an inhibitor of cytochrome P450 enzymes CYP1A2 and CYP2C19, necessitating further evaluation of potential drug interactions. Additionally, it did not exhibit hepatotoxicity or cardiotoxicity; however, it demonstrated mutagenic potential in the salmonella reverse mutation test (AMES), which is a genetic method that detects mutagenic chemical agents, thus justifying more complex confirmatory studies. <em>In vitro</em> assays showed that oxadiazole 2i has DPPH (2,2-diphenyl-1-picrylhydrazyl) radical reducing activity, indicating potential antioxidant properties with an IC<sub>50</sub> of 12.10 µg/mL. Concerning its leishmanicidal mechanism of action, molecular docking simulations at the active site of acetylcholinesterase demonstrated that the 2i molecule had superior binding energy values compared to the reference drug physostigmine (-7.39 kcal/mol versus −6.66 kcal/mol, respectively). However, the pharmacophore map revealed that physostigmine had more molecular interactions than oxadiazole 2i. In acetylcholinesterase inhibition assays, the 2i molecule exhibited significant inhibitory activity with an IC<sub>50</sub> of 11.91 µg/mL, suggesting a mechanism of action that compromises the parasitic membrane. Moreover, the 2i molecule demonstrated significant leishmanicidal activity against <em>L. infantum</em> with an IC<sub>50</sub> of 30.86 μM. Cytotoxicity assays on RAW 264.7 macrophages revealed a high CC<sub>50</sub> value of 485.5 µM and a selectivity index (SI) of 17.86. Based on these findings, oxadiazole 2i emerges as a promising candidate for further study, offering prospects for more affordable, selective, and less toxic leishmanicidal agents.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"262 ","pages":"Article 111674"},"PeriodicalIF":1.4,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143059190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Designing a multi-epitope subunit vaccine against Toxoplasma gondii through reverse vaccinology approach","authors":"Nadim Ahmed , Nurul Amin Rani , Tanjin Barketullah Robin , Md. Nafij Mashrur , Md Minhajul Islam Shovo , Anindita Ash Prome , Sadia Sultana , Mst Rubaiat Nazneen Akhand","doi":"10.1016/j.molbiopara.2024.111655","DOIUrl":"10.1016/j.molbiopara.2024.111655","url":null,"abstract":"<div><div>The parasite <em>Toxoplasma gondii</em>, or <em>T. gondii</em>, is zoonotic that both individuals as well as animals can contract resulting in toxoplasmosis, a life-threatening illness. We used an immunoinformatic technique in our research to construct a vaccine with multi-epitopes so that it can decrease the devastating impact caused by this dangerous parasite. In order to construct the vaccine, GRA6 and MIC3 proteins were targeted, which are engaged in <em>T. gondii</em> identification, infection, and immune response. Novel epitopes for linear B lymphocytes (LBL), cytotoxic T lymphocytes (CTL), and helper T lymphocytes (HTL) were found by epitope mapping, every anticipated epitope was assessed through rigorous screening to determine the top choices for epitopes which were entirely preserved, very antigenic in nature, nonallergenic, and nontoxic. 4 CTLs, 3 HTLs and 4 LBL epitopes were chosen and combined along with proper linkers and adjuvants to design a vaccine with several epitopes. Linkers as well as adjuvants were provided to make the vaccine more immunogenic, antigenic, and stable. The proposed vaccination was identified to possess the necessary biophysical properties, be soluble, extremely antigenic, and non-allergic. Reliability of the vaccine design was demonstrated by secondary along with tertiary structure prediction. It was anticipated that the vaccine's three-dimensional structure would likely link up with TLR-2 and TLR-4 via the investigation of molecular docking. TLR-2 and TLR-4 are crucial for the parasite's invasion and the body's response. In our docking investigation, both TLRs demonstrated strong binding affinities utilizing the vaccine structure. After that, the vaccine construct's elevated expression rate, which was observed in <em>Escherichia coli</em> strain K12, was confirmed by an investigation using in silico cloning and codon adaptation. The results of the research are really encouraging and some properties of the vaccine were found to be significantly better than existing the <em>T. gondii</em> multi-epitope vaccination based on the same proteins. Nonetheless, <em>in vivo</em> trials are strongly suggested for potential future studies.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"260 ","pages":"Article 111655"},"PeriodicalIF":1.4,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142624020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ao Zeng , Yongle Song , Xiaoting Wan , Bang Shen , Rui Fang , Junlong Zhao , Yanqin Zhou
{"title":"Characterization of two phosphatase 2 C domain-containing proteins PPM2A and PPM2B in Toxoplasma gondii","authors":"Ao Zeng , Yongle Song , Xiaoting Wan , Bang Shen , Rui Fang , Junlong Zhao , Yanqin Zhou","doi":"10.1016/j.molbiopara.2024.111654","DOIUrl":"10.1016/j.molbiopara.2024.111654","url":null,"abstract":"<div><div>Protein phosphatases Mg<sup>2+</sup>/Mn<sup>2+</sup> dependent (PPMs), serine/threonine phosphatases, are widely distributed in apicomplexan parasites, and <em>Toxoplasma gondii</em> possesses the largest number of PPMs in the apicomplexan parasites. Though the function of some PPMs has been characterized in <em>T. gondii</em>, much less is known about two phosphatase 2 C domain-containing proteins, PPM2A and PPM2B. PPM2A was identified as one of <em>Toxoplasma</em> Calmodulin's interacting proteins through proximity-based protein interaction BioID technology in the previous study, and PPM2B was the homolog of PPM2A in <em>T. gondii</em>. In this study, PPM2A was distributed in the whole tachyzoite of <em>T. gondii</em>, and PPM2B was mainly distributed in the cytoplasm by inserting a 10HA tag in the C-terminus of the two genes in the RH∆<em>ku80</em> strain. PPM2A knockout (Δ<em>ppm2a</em>), PPM2B knockout (Δ<em>ppm2b</em>), and double knockout (ΔΔ) in RHΔ<em>hxgprt</em> type I strain under CRISPR-Cas9 system did not result in intracellular replication defect. Besides, mouse experiments demonstrated that PPM2A, PPM2B, and double knockout did not reduce the pathogenicity of <em>T. gondii</em> compared with the RH∆<em>hxgprt</em> strain. However, the plaque size of these single knockout and double knockout strains were smaller than that in the control RH∆<em>hxgprt</em> strain. Our results provide new insight into the function of PPMs in the pathogenesis of <em>T. gondii</em>.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"260 ","pages":"Article 111654"},"PeriodicalIF":1.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Martin Ciganda , Andrew P. Jackson , James D. Bangs
{"title":"Diversification of sphingolipid synthase activities in kinetoplastid protozoa","authors":"Martin Ciganda , Andrew P. Jackson , James D. Bangs","doi":"10.1016/j.molbiopara.2024.111656","DOIUrl":"10.1016/j.molbiopara.2024.111656","url":null,"abstract":"<div><div>Phosphosphingolipids (PSL) are essential components of eukaryotic membranes. The major PSL in fungi and protists is inositol phosphorylceramide (IPC), while sphingomyelin (SM), and to a lesser extent ethanolamine phosphorylceramide (EPC) predominate in mammals. Most kinetoplastid protozoa have a syntenic locus that encodes a single sphingolipid synthase (<em>SLS</em>) gene. Uniquely, among the kinetoplastids, the salivarian (African) trypanosomes have expanded this locus from a single gene in <em>Trypanosoma vivax</em> (<em>TvSLS</em>) to four genes in <em>T. brucei</em> (<em>TbSLS1-4</em>). We have previously shown that one of these is an IPC synthase, while the others are SM/EPC synthases, and that specificity is controlled by a single signature residue (IPC, serine; SM/EPC, phenylalanine). This residue is serine in <em>T. cruz</em>i and <em>Leishmania major</em> SLSs, both of which are demonstrated IPC synthases. However, <em>T. vivax</em> has a tyrosine at this residue raising the issue of specificity. Using a liposome-supplemented <em>in vitro</em> translation system we now show that <em>T. vivax</em> SLS is an SM/EPC synthase, and that the basal kinetoplastid <em>Bodo saltans</em> SLS is an IPC synthase (serine). We use these data, and a multiple alignment of available sequences, to discuss the evolution of kinetoplastid SLSs and their unique expansion in <em>T. brucei</em> and related salivarian trypanosomes.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"260 ","pages":"Article 111656"},"PeriodicalIF":1.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Desirée O. Alves , Rob Geens , Hiam R. da Silva Arruda , Lisa Jennen , Sam Corthaut , Ellen Wuyts , Guilherme Caldas de Andrade , Francisco Prosdocimi , Yraima Cordeiro , José Ricardo Pires , Larissa Rezende Vieira , Guilherme A.P. de Oliveira , Yann G.-J. Sterckx , Didier Salmon
{"title":"Biophysical analysis of the membrane-proximal Venus Flytrap domain of ESAG4 receptor-like adenylate cyclase from Trypanosoma brucei","authors":"Desirée O. Alves , Rob Geens , Hiam R. da Silva Arruda , Lisa Jennen , Sam Corthaut , Ellen Wuyts , Guilherme Caldas de Andrade , Francisco Prosdocimi , Yraima Cordeiro , José Ricardo Pires , Larissa Rezende Vieira , Guilherme A.P. de Oliveira , Yann G.-J. Sterckx , Didier Salmon","doi":"10.1016/j.molbiopara.2024.111653","DOIUrl":"10.1016/j.molbiopara.2024.111653","url":null,"abstract":"<div><div>The protozoan parasite <em>Trypanosoma brucei</em> possesses a large family of transmembrane receptor-like adenylate cyclases (RACs), primarily located to the flagellar surface and involved in sensing of the extracellular environment. RACs exhibit a conserved topology characterized by a large N-terminal extracellular moiety harbouring two Venus Flytrap (VFT) bilobate structures separated from an intracellular catalytic domain by a single transmembrane helix. RAC activation, which typically occurs under mild acid stress, requires the dimerization of the intracellular catalytic domain. The occurrence of VFT domains in the RAC’s extracellular moiety suggests their potential responsiveness to extracellular ligands in the absence of stress, although no such ligands have been identified so far. Herein we report the biophysical characterization of the membrane-proximal VFT2 domain of a bloodstream form-specific RAC called ESAG4, whose ectodomain 3D structure is completely unknown. The paper describes an AlphaFold2-based optimisation of the expression construct, enabling facile and high-yield recombinant production and purification of the target protein. Through an interdisciplinary approach combining various biophysical methods, we demonstrate that the optimised VFT2 domain obtained by recombination is properly folded and behaves as a monomer in solution. The latter suggests a ligand-binding capacity independent of dimerization, unlike typical mammalian VFT receptors, as guanylate cyclase. <em>In silico</em> VFT2 genomic analyses shows divergence among cyclase isoforms, hinting at ligand specificity. Taken together this improved procedure enabling facile and high-yield recombinant production and purification of the target protein could benefit researchers studying trypanosomal RAC VFT domains but also any trypanosome domain with poorly defined boundaries. Additionally, our findings support the stable monomeric VFT2 domain as a useful tool for future structural investigations and ligand screening.</div></div>","PeriodicalId":18721,"journal":{"name":"Molecular and biochemical parasitology","volume":"260 ","pages":"Article 111653"},"PeriodicalIF":1.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142504309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}