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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus continues to cause severe disease and deaths in many parts of the world, despite massive vaccination efforts. Antiviral drugs to curb an ongoing infection remain a priority. The virus-encoded 3C-like main protease (MPro; nsp5) is seen as a promising target. Here, with a positive selection genetic system engineered in Saccharomyces cerevisiae using cleavage and release of MazF toxin as an indicator, we screened in a robotized setup small molecule libraries comprising ~2,500 compounds for MPro inhibitors. We detected eight compounds as effective against MPro expressed in yeast, five of which are characterized proteasome inhibitors. Molecular docking indicates that most of these bind covalently to the MPro catalytically active cysteine. Compounds were confirmed as MPro inhibitors in an in vitro enzymatic assay. Among those were three previously only predicted in silico; the boron-containing proteasome inhibitors bortezomib, delanzomib, and ixazomib. Importantly, we establish reaction conditions in vitro preserving the MPro-inhibitory activity of the boron-containing drugs. These differ from the standard conditions, which may explain why boron compounds have gone undetected in screens based on enzymatic in vitro assays. Our screening system is robust and can find inhibitors of a specific protease that are biostable, able to penetrate a cell membrane, and are not generally toxic. As a cellular assay, it can detect inhibitors that fail in a screen based on an in vitro enzymatic assay using standardized conditions, and now give support for boron compounds as MPro inhibitors. This method can also be adapted for other viral proteases.IMPORTANCEThe coronavirus disease 2019 (COVID-19) pandemic triggered the realization that we need flexible approaches to find treatments for emerging viral threats. We implemented a genetically engineered platform in yeast to detect inhibitors of the virus's main protease (MPro), a promising target to curb severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Screening molecule libraries, we identified candidate inhibitors and verified them in a biochemical assay. Moreover, the system detected boron-containing molecules as MPro inhibitors. Those were previously predicted computationally but never shown effective in a biochemical assay. Here, we demonstrate that they require a non-standard reaction buffer to function as MPro inhibitors. Hence, our cell-based method detects protease inhibitors missed by other approaches and provides support for the boron-containing molecules. We have thus demonstrated that our platform can screen large numbers of chemicals to find potential inhibitors of a viral protease. Importantly, the platform can be modified to detect protease targets from other emerging viruses.
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Adaptation to the shortage in free amino acids (AA) is mediated by 2 pathways, the integrated stress response (ISR) and the mechanistic target of rapamycin (mTOR). In response to reduced levels, primarily of leucine or arginine, mTOR in its complex 1 configuration (mTORC1) is suppressed leading to a decrease in translation initiation and elongation. The eIF2α kinase general control nonderepressible 2 (GCN2) is activated by uncharged tRNAs, leading to induction of the ISR in response to a broader range of AA shortage. ISR confers a reduced translation initiation, while promoting the selective synthesis of stress proteins, such as ATF4. To efficiently adapt to AA starvation, the 2 pathways are cross-regulated at multiple levels. Here we identified a new mechanism of ISR/mTORC1 crosstalk that optimizes survival under AA starvation, when mTORC1 is forced to remain active. mTORC1 activation during acute AA shortage, augmented ATF4 expression in a GCN2-dependent manner. Under these conditions, enhanced GCN2 activity was not dependent on tRNA sensing, inferring a different activation mechanism. We identified a labile physical interaction between GCN2 and mTOR that results in a phosphorylation of GCN2 on serine 230 by mTOR, which promotes GCN2 activity. When examined under prolonged AA starvation, GCN2 phosphorylation by mTOR promoted survival. Our data unveils an adaptive mechanism to AA starvation, when mTORC1 evades inhibition.
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Herein the first example of conversion of alcohols into carboxylic acids by use of the Dess-Martin Periodinane (DMP), which is otherwise routinely employed for the conversion to aldehydes, is reported. This methodology will have significant potential utility in the synthesis of cytidine analogues and other related biologically important molecules.
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Malaria remains a significant public health challenge, with Plasmodium vivax being the species responsible for the most prevalent form of the disease. Given the limited therapeutic options available, the search for new antimalarials against P. vivax is urgent. This study aims to identify new inhibitors for P. vivax N-myristoyltransferase (PvNMT), an essential drug target against malaria. Through a validated virtual screening campaign, we prioritized 23 candidates for further testing. In the yeast NMT system, seven compounds exhibit a potential inhibitor phenotype. In vitro antimalarial phenotypic assays confirmed the activity of four candidates while demonstrating an absence of cytotoxicity. Enzymatic assays reveal LabMol-394 as the most promising inhibitor, displaying selectivity against the parasite and a strong correlation within the yeast system. Furthermore, molecular dynamics simulations shed some light into its binding mode. This study constitutes a substantial contribution to the exploration of a selective quinoline scaffold and provides valuable insights into the development of new antimalarial candidates.
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BACKGROUND: In 2021, Uganda's neonatal mortality rate was approximately 19 deaths per 1000 live births, with an estimated stillbirth rate of 15.1 per 1000 total births. Data are critical for indicating areas where deaths occur and why, hence driving improvements. Many countries rely on surveys like Demographic and Health Surveys (DHS), which face challenges with respondents' misinterpretation of questions. However, little is documented about this in Uganda. Cognitive interviews aim to improve questionnaires and assess participants' comprehension of items. Through cognitive interviews we explored women's interpretations of questions on pregnancy and pregnancy outcomes. METHODS: In November 2021, we conducted cognitive interviews with 20 women in Iganga Mayuge health and demographic surveillance system site in eastern Uganda. We adapted the reproductive section of the DHS VIII women's questionnaire, purposively selected questions and used concurrent verbal probing. Participants had secondary school education and were English speaking. Cognition was measured through comparing instructions in the DHS interviewers' manual to participants' responses and researcher's knowledge. A qualitative descriptive approach to analysis was undertaken. RESULTS: We report findings under the cognitive aspect of comprehension. Some questions were correctly understood, especially those with less technical terms or without multiple sections. Most participants struggled with questions asking whether the woman has her living biological children residing with her or not. Indeed, some thought it referred to how many living children they had. There were comprehension difficulties with long questions like 210 that asks about miscarriages, newborn deaths, and stillbirths together. Participants had varying meanings for miscarriages, while many misinterpreted stillbirth, not linking it to gestational age. Furthermore, even amongst educated women some survey questions were misunderstood. CONCLUSIONS: Population surveys may misclassify, over or under report events around pregnancy and pregnancy outcomes. Interviewers should begin with a standard definition of key terms and ensure respondents understand these. Questions can be simplified through breaking up long sentences, while interviewer training should be modified to ensure they thoroughly understand key terms. We recommend cognitive interviews while developing survey tools, beyond basic pre-testing. Improving respondents' comprehension and thus response accuracy will increase reporting and data quality.
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Aborto Espontâneo , Natimorto , Gravidez , Recém-Nascido , Criança , Feminino , Humanos , Natimorto/epidemiologia , Uganda/epidemiologia , Aborto Espontâneo/epidemiologia , Inquéritos e Questionários , CogniçãoRESUMO
The flavonoid Quercetin (Qe) was identified as an activator of Inositol-requiring enzyme 1 (IRE1) in S. cerevisiae (scIre1p), but its impact on human IRE1 (hIRE1) remains controversial due to the absence of a conserved Qe binding site. We have explored the binding modes and effect of Qe on both scIre1p and hIRE1 dimers using in silico and in vitro approaches. The activation site in scIre1p stably accommodates both Qe and its derivative Quercitrin (Qi), thus enhancing the stability of the RNase pocket. However, the corresponding region in hIRE1 does not bind any of the two molecules. Instead, we show that both Qe and Qi block the RNase activity of hIRE1 in vitro, with sub-micromolar IC50 values. Our results provide a rationale for why Qe is an activator in scIre1p but a potent inhibitor in hIRE1. The identification of a new allosteric site in hIRE1 opens a promising window for drug development and UPR modulation.
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Inositol-requiring enzyme 1 (IRE1) is a transmembrane sensor that is part of a trio of sensors responsible for controlling the unfolded protein response within the endoplasmic reticulum (ER). Upon the accumulation of unfolded or misfolded proteins in the ER, IRE1 becomes activated and initiates the cleavage of a 26-nucleotide intron from human X-box-containing protein 1 (XBP1). The cleavage is mediated by the RtcB ligase enzyme, which splices together two exons, resulting in the formation of the spliced isoform XBP1s. The XBP1s isoform activates the transcription of genes involved in ER-associated degradation to maintain cellular homeostasis. The catalytic activity of RtcB is controlled by the phosphorylation and dephosphorylation of three tyrosine residues (Y306, Y316, and Y475), which are regulated by the ABL1 tyrosine kinase and PTP1B phosphatase, respectively. This study focuses on investigating the mechanism by which the PTP1B phosphatase activates the RtcB ligase using a range of advanced in silico methods. Protein-protein docking identified key interacting residues between RtcB and PTP1B. Notably, the phosphorylated Tyr306 formed hydrogen bonds and salt bridge interactions with the "gatekeeper" residues Arg47 and Lys120 of the inactive PTP1B. Classical molecular dynamics simulation emphasized the crucial role of Asp181 in the activation of PTP1B, driving the conformational change from an open to a closed state of the WPD-loop. Furthermore, QM/MM-MD simulations provided insights into the free energy landscape of the dephosphorylation reaction mechanism of RtcB, which is mediated by the PTP1B phosphatase.
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Ligases , Monoéster Fosfórico Hidrolases , Humanos , Ligases/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Fosforilação , Isoformas de Proteínas/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismoRESUMO
Post-translational modifications (PTMs) add a major degree of complexity to the proteome and are essential controllers of protein homeostasis. Amongst the hundreds of PTMs identified, ubiquitin and ubiquitin-like (UBL) modifications are recognized as key regulators of cellular processes through their ability to affect protein-protein interactions, protein stability, and thus the functions of their protein targets. Here, we focus on the most recently identified UBL, ubiquitin-fold modifier 1 (UFM1), and the machinery responsible for its transfer to substrates (UFMylation) or its removal (deUFMylation). We first highlight the biochemical peculiarities of these processes, then we develop on how UFMylation and its machinery control various intertwined cellular processes and we highlight some of the outstanding research questions in this emerging field.
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Proteínas , Ubiquitina , Ubiquitina/metabolismo , Proteínas/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Processamento de Proteína Pós-Traducional , Comunicação CelularRESUMO
Pseudomonas aeruginosa is an opportunistic pathogen prone to developing drug-resistance and is a major cause of infection for burn patients and patients suffering from cystic fibrosis or are hospitalized in intensive care units. One of the virulence factors of this bacterium is the lipase enzyme that degrades the extracellular matrix of the host tissue and promotes invasion. Bromhexine is a mucolytic drug and has recently been reported to function as a competitive inhibitor of lipase with an IC50 value of 49 µM. In the present study, an attempt was made to identify stronger inhibitors from the ChEMBL database of bioactive compounds, as compared to the reference compound Bromhexine. Following docking and MD simulations, four hit compounds (N1-N4) were selected that showed promising binding modes and low RMSD values indicative of stable protein-ligand complexes. From subsequent binding pose metadynamics (BPMD) simulations, two of these (N2 and N4) stood out as more potent than Bromhexine, displaying stable interactions with residues in the catalytic site of the enzyme. Biological investigations were performed for all four compounds. Among them, the same two hit compounds were found to be the most effective binders with IC50 values of 22.1 and 27.5 µM, respectively; i.e. roughly twice as efficient as the reference Bromhexine. Taken together, our results show that these hits can be promising new candidates to use as leads for the development of drugs targeting the P. aeruginosa lipase enzyme.Communicated by Ramaswamy H. Sarma.
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Bromoexina , Pseudomonas aeruginosa , Humanos , Lipase , Simulação de Acoplamento Molecular , Inibidores Enzimáticos/farmacologia , Simulação de Dinâmica MolecularRESUMO
To be functional, some RNAs require a processing step involving splicing events. Each splicing event necessitates an RNA ligation step. RNA ligation is a process that can be achieved with various intermediaries such as self-catalysing RNAs, 5'-3' and 3'-5' RNA ligases. While several types of RNA ligation mechanisms occur in human, RtcB is the only 3'-5' RNA ligase identified in human cells to date. RtcB RNA ligation activity is well known to be essential for the splicing of XBP1, an essential transcription factor of the unfolded protein response; as well as for the maturation of specific intron-containing tRNAs. As such, RtcB is a core factor in protein synthesis and homeostasis. Taking advantage of the high homology between RtcB orthologues in archaea, bacteria and eukaryotes, this review will provide an introduction to the structure of RtcB and the mechanism of 3'-5' RNA ligation. This analysis is followed by a description of the mechanisms regulating RtcB activity and localisation, its known partners and its various functions from bacteria to human with a specific focus on human cancer.
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RNA Ligase (ATP) , Fatores de Transcrição , Humanos , RNA Ligase (ATP)/genética , RNA Ligase (ATP)/química , RNA Ligase (ATP)/metabolismo , Fatores de Transcrição/metabolismo , RNA/metabolismo , Resposta a Proteínas não Dobradas , RNA de Transferência/genética , RNA de Transferência/metabolismo , Splicing de RNA/genéticaRESUMO
BACKGROUND: In 2021, Uganda had an estimated 25,855 stillbirths and 32,037 newborn deaths. Many Adverse Pregnancy Outcomes (APOs) go unreported despite causing profound grief and other mental health effects. This study explored psychosocial effects of APOs and their influence on reporting these events during surveys and surveillance settings in Uganda. METHODS: A qualitative cross-sectional study was conducted in September 2021 in Iganga Mayuge health and demographic surveillance system site, eastern Uganda. Narratives were held with 44 women who had experienced an APO (miscarriage, stillbirth or neonatal death) and 7 men whose spouses had undergone the same. Respondents were purposively selected and the sample size premised on the need for diverse respondents. Reflexive thematic analysis was undertaken, supported by NVivo software. RESULTS: 60.8% of respondents had experienced neonatal deaths, 27.4% stillbirths, 11.8% miscarriages and almost half had multiple APOs. Theme one on psychosocial effects showed that both women and men suffered disbelief, depression, shame and thoughts of self-harm. In theme two on reactions to interviews, most respondents were reminded about their loss. Indeed, some women cried and a few requested termination of the interview. However, many said they eventually felt better, especially where interviewers comforted and advised them. In theme three about why people consent to such interviews, it was due to the respondents' need for sensitization on causes of pregnancy loss and danger signs, plus the expectation that the interview would lead to improved health services. Theme four on suggestions for improving interviews highlighted respondents' requests for a comforting and encouraging approach by interviewers. CONCLUSION: Psychosocial effects of APOs may influence respondents' interest and ability to effectively engage in an interview. Findings suggest that a multi-pronged approach, including interviewer training in identifying and dealing responsively with grieving respondents, and meeting needs for health information and professional counselling could improve reporting of APOs in surveys and surveillance settings. More so, participants need to understand the purpose of the interview and have realistic expectations.
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Aborto Espontâneo , Morte Perinatal , Masculino , Recém-Nascido , Gravidez , Feminino , Humanos , Aborto Espontâneo/epidemiologia , Resultado da Gravidez , Natimorto/epidemiologia , Estudos Transversais , Uganda/epidemiologia , Inquéritos e QuestionáriosRESUMO
Inositol-requiring enzyme 1 (IRE1) is a major mediator of the unfolded protein response (UPR), which is activated upon endoplasmic reticulum (ER) stress. Tumor cells experience ER stress due to adverse microenvironmental cues, a stress overcome by relying on IRE1 signaling as an adaptive mechanism. Herein, we report the discovery of structurally new IRE1 inhibitors identified through the structural exploration of its kinase domain. Characterization in in vitro and in cellular models showed that they inhibit IRE1 signaling and sensitize glioblastoma (GB) cells to the standard chemotherapeutic, temozolomide (TMZ). Finally, we demonstrate that one of these inhibitors, Z4P, permeates the blood-brain barrier (BBB), inhibits GB growth, and prevents relapse in vivo when administered together with TMZ. The hit compound disclosed herein satisfies an unmet need for targeted, non-toxic IRE1 inhibitors and our results support the attractiveness of IRE1 as an adjuvant therapeutic target in GB.
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Methylenetetrahydrofolate dehydrogenase (MTHFD2) is a mitochondrial enzyme involved in 1â C metabolism that is upregulated in various cancer cells, but absent in normal proliferating cells. Xanthine derivatives are the first selective inhibitors of MTHFD2 which bind to its allosteric site. Xanthine derivatives (including the co-crystallized inhibitors) were herein interrogated by molecular/induced-fit docking, MM-GBSA binding free energy calculations and molecular dynamics simulations in both MTHFD2 and MTHFD1 (a close homolog expressed in healthy cells). The gained insights from our in silico protocol allowed us to study binding mode, key protein-ligand interactions and dynamic movement of the allosteric inhibitors, correlating with their experimental binding affinities, biological activities and selectivity for MTHFD2. The reported conformational changes with MTHFD2 upon binding of xanthine derivatives were furthermore evaluated and confirmed by RMSF analyses of the MD simulation trajectories. The results reported herein are expected to benefit in the rational design of selective MTHFD2 allosteric inhibitors.
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Metilenotetra-Hidrofolato Desidrogenase (NADP) , Simulação de Dinâmica Molecular , Sítio Alostérico , Metilenotetra-Hidrofolato Desidrogenase (NADP)/química , Metilenotetra-Hidrofolato Desidrogenase (NADP)/metabolismo , Xantina , Simulação de Acoplamento MolecularRESUMO
Unfolded protein response (UPR)-dependent metabolic reprogramming diverts metabolites from glycolysis to mitochondrial 1C metabolism, highlighting pharmacological resistance to folate drugs and overexpression of certain enzymes. Methylenetetrahydrofolate dehydrogenase (MTHFD2) is a mitochondrial enzyme that plays a key role in 1C metabolism in purine and thymidine synthesis and is exclusively overexpressed in cancer cells but absent in most healthy adult human tissues. To the best of our knowledge, tricyclic coumarin-based compounds (substrate site binders) and xanthine derivatives (allosteric site binders) are the only selective inhibitors of MTHFD2 reported until the present date. The current study aims at the investigation of the available structural data of MTHFD2 in complex with potent and selective inhibitors that occupy the substrate binding site, further providing insights into binding mode, key protein-ligand interactions, and conformational dynamics, that correspond to the experimental binding affinities and biological activities. In addition, we carried out structure-based drug design on the substrate binding site of MTHFD2, by exploiting the cocrystal structure of MTHFD2 with the tricyclic coumarin-based inhibitor. The structure-based drug design campaign involves R-group enumeration, bioisostere replacement, molecular docking, ADME prediction, MM-GBSA binding free energy calculations, and molecular dynamics simulations, that led to a small library of new and potential compounds, capable of selectively inhibiting MTHFD2. The results reported herein are expected to benefit medicinal chemists working on the development of selective MTHFD2 inhibitors for cancer treatment, although experimental validation by biochemical and/or pharmacokinetic assays is required to substantiate the outcomes of the study.
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BACKGROUND: Universal coverage of evidence-based interventions for perinatal health, often part of evidence-based guidelines, could prevent most perinatal deaths, particularly if entire communities were engaged in the implementation. Social innovations may provide creative solutions to the implementation of evidence-based guidelines, but successful use of social innovations relies on the engagement of communities and health system actors. This proof-of-concept study aimed to assess whether an earlier successful social innovation for improved neonatal survival that employed regular facilitated Plan-Do-Study-Act meetings on the commune level was feasible and acceptable when implemented on multiple levels of the health system (52 health units) and resulted in actions with plausibly favourable effects on perinatal health and survival in Cao Bang province, northern Vietnam. METHODS: The Integrated Promoting Action on Research Implementation in Health Services (i-PARIHS) framework guided the implementation and evaluation of the Perinatal Knowledge-Into-Practice (PeriKIP) project. Data collection included facilitators' diaries, health workers' knowledge on perinatal care, structured observations of antenatal care, focus group discussions with facilitators, their mentors and representatives of different actors of the initiated stakeholder groups and an individual interview with the Reproductive Health Centre director. Clinical experts assessed the relevance of the identified problems and actions taken based on facilitators' diaries. Descriptive statistics included proportions, means, and t-tests for the knowledge assessment and observations. Qualitative data were analysed by content analysis. RESULTS: The social innovation resulted in the identification of about 500 relevant problems. Also, 75% of planned actions to overcome prioritised problems were undertaken, results presented and a plan for new actions to achieve the group's goals to enhance perinatal health. The facilitators had significant roles, ensuring that the stakeholder groups were established based on principles of mutual respect. Overall, the knowledge of perinatal health and performance of antenatal care improved over the intervention period. CONCLUSIONS: The establishment of facilitated local stakeholder groups can remedy the need for tailored interventions and grassroots involvement in perinatal health and provide a scalable structure for focused efforts to reduce preventable deaths and promote health and well-being.
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BACKGROUND: Implementing and sustaining innovations in clinical practice, such as evidence-based practices, programmes, and policies, is frequently described as challenging. Facilitation as a strategy for supporting implementation requires a facilitator, i.e. an individual with a designated role to support the implementation process. A growing number of studies report that facilitation can help tackle the challenges in implementation efforts. To optimise the potential contribution of facilitation as a strategy to improve the implementation of new practices, there is a need to enhance understanding about what training and support is required for individuals in the facilitator role. The objective of this scoping review is to map how facilitators have been trained for, and supported in, the facilitator role in implementation studies in health and community care. Specifically, the review aims to examine what is reported on training and support of facilitators in terms of learning outcomes, content, dose, mode of delivery, learning activities, and qualifications of the trainers and how the facilitators perceive training and support. METHODS: This scoping review will follow the guidance of the Joanna Briggs Institute and the PRISMA Extension for Scoping Review checklist. We will include articles in which (a) facilitation is deployed as an implementation strategy, with identified facilitator roles targeting staff and managers, to support the implementation of specified innovations in health or community care, and (b) training and/or support of facilitators is reported. We will exclude articles where facilitation is directed to education or training in specific clinical procedures or if facilitation supports the implementation of general quality improvement systems. All types of peer-reviewed studies and study protocols published in English will be included. A systematic search will be performed in MEDLINE (Ovid), Embase (embase.com), Web of Science Core Collection, and CINAHL (Ebsco). DISCUSSION: The proposed scoping review will provide a systematic mapping of the literature on the training and support of implementation facilitators and contribute useful knowledge within the field of implementation science to inform future facilitation initiatives. SYSTEMATIC REVIEW REGISTRATION: Registered at Open Science Framework (registration https://doi.org/10.17605/OSF.IO/M6NPQ ).
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Lista de Checagem , Aprendizagem , Humanos , Escolaridade , Ciência da Implementação , MEDLINE , Revisões Sistemáticas como AssuntoRESUMO
Exotoxin A (ETA) is an extracellular secreted toxin and a single-chain polypeptide with A and B fragments that is produced by Pseudomonas aeruginosa. It catalyzes the ADP-ribosylation of a post-translationally modified histidine (diphthamide) on eukaryotic elongation factor 2 (eEF2), which results in the inactivation of the latter and the inhibition of protein biosynthesis. Studies show that the imidazole ring of diphthamide plays an important role in the ADP-ribosylation catalyzed by the toxin. In this work, we employ different in silico molecular dynamics (MD) simulation approaches to understand the role of diphthamide versus unmodified histidine in eEF2 on the interaction with ETA. Crystal structures of the eEF2-ETA complexes with three different ligands NAD+, ADP-ribose, and ßTAD were selected and compared in the diphthamide and histidine containing systems. The study shows that NAD+ bound to ETA remains very stable in comparison with other ligands, enabling the transfer of ADP-ribose to the N3 atom of the diphthamide imidazole ring in eEF2 during ribosylation. We also show that unmodified histidine in eEF2 has a negative impact on ETA binding and is not a suitable target for the attachment of ADP-ribose. Analyzing of radius of gyration and COM distances for NAD+, ßTAD, and ADP-ribose complexes revealed that unmodified His affects the structure and destabilizes the complex with all different ligands throughout the MD simulations.
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Histidina , Simulação de Dinâmica Molecular , Fator 2 de Elongação de Peptídeos/química , Histidina/química , NAD/metabolismo , Adenosina Difosfato Ribose/metabolismo , Pseudomonas aeruginosa , Exotoxina A de Pseudomonas aeruginosaRESUMO
Ganglioside-monosialic acid (GM1) gangliosidosis, a rare autosomal recessive disorder, is frequently caused by deleterious single nucleotide variants (SNVs) in GLB1 gene. These variants result in reduced ß-galactosidase (ß-gal) activity, leading to neurodegeneration associated with premature death. Currently, no effective therapy for GM1 gangliosidosis is available. Three ongoing clinical trials aim to deliver a functional copy of the GLB1 gene to stop disease progression. In this study, we show that 41% of GLB1 pathogenic SNVs can be replaced by adenine base editors (ABEs). Our results demonstrate that ABE efficiently corrects the pathogenic allele in patient-derived fibroblasts, restoring therapeutic levels of ß-gal activity. Off-target DNA analysis did not detect off-target editing activity in treated patient's cells, except a bystander edit without consequences on ß-gal activity based on 3D structure bioinformatics predictions. Altogether, our results suggest that gene editing might be an alternative strategy to cure GM1 gangliosidosis.
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Gangliosidose GM1 , Humanos , Gangliosidose GM1/terapia , Gangliosidose GM1/tratamento farmacológico , beta-Galactosidase/genética , beta-Galactosidase/química , beta-Galactosidase/metabolismo , Edição de Genes , Sistemas CRISPR-Cas/genética , AlelosRESUMO
CD95 is a member of the TNF receptor superfamily that is ubiquitously expressed in healthy and pathological tissues. Stimulation of CD95 by its physiological ligand CD95L induces its oligomerization leading in turn to the transduction of either apoptotic or nonapoptotic signals. CD95L can exist as both membrane-anchored and soluble forms (sCD95L), the latter resulting from the proteolytic cleavage of the former. Candidate proteases able to achieve CD95L cleavage were identified as matrix metalloproteases (MMP) due to their demonstrated ability to cleave other TNF superfamily ligands. The main goal of this study was to systematically identify the MMP family members capable of cleaving CD95L and subsequently determine the corresponding cleavage sites. By using different orthogonal biochemical approaches and combining them with molecular modelling, we confirmed data from the literature regarding CD95L cleavage by MMP-3 and MMP-7. Moreover, we found that MMP-2 and MMP-12 can cleave CD95L and characterized their resulting cleavage sites. This study provides a systematic approach to analyse the cleavage of CD95L, which until now had only been poorly described.