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AIM: To evaluate the effect on type 2 diabetes remission of short-term intensive metabolic intervention consisting of frequent dietary, exercise and diabetes management coaching, metformin and fixed-ratio insulin degludec/liraglutide. METHODS: In a multicentre open-label randomized controlled trial, insulin-naïve participants within 5 years of diabetes diagnosis were assigned to a 16-week remission intervention regimen or standard care, and followed for relapse of diabetes and sustained remission for an additional year after stopping glucose-lowering drugs. RESULTS: A total of 159 participants aged 57 ± 10 years, with diabetes duration 2.6 ± 1.5 years, body mass index 33.5 ± 6.5 kg/m2, and glycated haemoglobin (HbA1c) level 53 ± 7 mmol/mol were randomized and analysed (79 intervention, 80 control). At the end of the 16-week intervention period, compared to controls, intervention participants achieved lower HbA1c levels (40 ± 4 vs. 51 ± 7 mmol/mol; p < 0.0001), and lost more weight (3.3 ± 4.4% vs. 1.9 ± 3.0%; p = 0.02). There was a lower hazard of diabetes relapse overall in the intervention group compared to controls (hazard ratio 0.63, 95% confidence interval [CI] 0.45, 0.88; p = 0.007), although this was not sustained over time. Remission rates in the intervention group were not significantly higher than in the control group at 12 weeks (17.7% vs. 12.5%, relative risk [RR] 1.42, 95% CI 0.67, 3.00; p = 0.36) or at 52 weeks (6.3% vs. 3.8%, RR 1.69, 95% CI 0.42, 6.82) following the intervention period. CONCLUSIONS: An intensive remission-induction intervention including fixed-ratio insulin degludec/liraglutide reduced the risk of type 2 diabetes relapse within 1 year without sustained remission.
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Background: Polycystic ovary syndrome (PCOS) is the most common metabolic-endocrine disorder impacting the health and quality of life of women over the lifespan. Evidence-based data on the scope of adverse health outcomes in those affected by PCOS is critical to improve healthcare and quality of life in this population. The aim of this study was to determine the prevalence of adverse health outcomes in those with PCOS compared to age-matched controls. Methods: We conducted a retrospective observational case-control study in those diagnosed with PCOS and age-matched controls using the Alberta Health Services Health Analytics database and the International Classification of Diseases, for the period from 2002-2018 in Alberta, Canada. Results: The cohort consisted of n = 16,531 exposed PCOS cases and n = 49,335 age-matched un-exposed controls. The prevalences of hypertension, renal disease, gastrointestinal disease, eating disorders, mental illness, depression-anxiety, rheumatoid arthritis, respiratory infections, and all malignancies were 20%-40% (P < 0.0001) higher in those with PCOS, compared to controls. The prevalence of obesity, dyslipidemia, nonalcoholic fatty liver disease, and type 2 diabetes was 2-3 fold higher in those with PCOS (P < 0.001). Cardiovascular, cerebrovascular, and peripheral vascular disease were 30%-50% higher, and they occurred 3-4 years earlier in those with PCOS (P < 0.0001); a 2-fold higher prevalence of dementia occurred in those with PCOS, compared to controls. Conclusion: These findings provide evidence that PCOS is associated with a higher prevalence of morbidities over the lifespan, and the potential scope of the healthcare burden in women affected by PCOS.
Contexte: Le syndrome des ovaires polykystiques (SOPK) est le trouble métabolique et endocrinien le plus courant à toucher la santé et la qualité de vie des femmes de tout âge. Il est essentiel de disposer de données probantes sur l'ampleur des effets néfastes sur la santé des personnes qui en sont atteintes afin d'améliorer les soins de santé offerts à cette population et sa qualité de vie. Le but de la présente étude était de déterminer la prévalence des effets néfastes sur la santé des personnes atteintes du SOPK et de les comparer aux effets chez des témoins appariés selon l'âge. Méthodologie: Nous avons mené une étude cas-témoin observationnelle rétrospective chez des personnes diagnostiquées avec un SOPK et des témoins appariés selon l'âge en utilisant la base des données analytiques de santé de l'Alberta Health Services et la classification internationale des maladies pour l'Alberta (Canada) de 2002 à 2018. Résultats: La cohorte à l'étude était composée de cas de SOPK (n = 16 531) et de témoins appariés selon l'âge qui n'y étaient pas exposés (n = 49 335). L'hypertension, les maladies rénales, les maladies gastro-intestinales, les troubles alimentaires, les troubles de santé mentale, la dépression et l'anxiété, la polyarthrite rhumatoïde, les infections respiratoires, et les cancers de tout type étaient de 20 % à 40 % plus fréquents (p < 0,0001) chez les personnes atteintes de SOPK que chez les témoins. La prévalence de l'obésité, de la dyslipidémie, de la stéatose hépatique non alcoolique et du diabète de type 2 était 2 à 3 fois plus élevée chez les personnes atteintes de SOPK (p < 0,001). L'incidence des maladies cardiovasculaires, vasculaires cérébrales et vasculaires périphériques était 30 % à 50 % plus élevée et ces maladies survenaient 3 à 4 ans plus tôt chez les personnes atteintes de SOPK (p < 0,0001), et la prévalence de démence était 2 fois plus élevée chez les personnes atteintes de SOPK que chez les témoins. Conclusions: Ces résultats démontrent que le SOPK est associé à une prévalence plus élevée de morbidité tout au long de la vie et démontrent l'ampleur possible du fardeau en soins de santé chez les femmes touchées par le SOPK.
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Polycystic ovary syndrome (PCOS) is the most common endocrine-metabolic disorder affecting females across the lifespan. Eating disorders (EDs) are psychiatric conditions that may impact the development of PCOS and comorbidities including obesity, metabolic syndrome, and type 2 diabetes. The aim of this scoping review was to determine the prevalence of EDs and disordered eating, and to review the etiology of EDs in PCOS. The review was conducted using search terms addressing PCOS, EDs, and disordered eating in databases, including PubMed, Scopus, PsycINFO, and CINAHL. Structured interviews, self-administered questionnaires, chart review, or self-reported diagnosis were used to identify EDs in 38 studies included in the review. The prevalence of any ED in those with PCOS ranged from 0% to 62%. Those with PCOS were 3-6-fold more likely to have an ED and higher odds ratios (ORs) of an elevated ED score compared with controls. In those with PCOS, 30% had a higher OR of bulimia nervosa and binge ED was 3-fold higher compared with controls. Studies were limited on anorexia nervosa and other specified feeding or ED (such as night eating syndrome) and these were not reported to be higher in PCOS. To our knowledge, no studies reported on avoidant/restrictive food intake disorder, rumination disorder, or pica in PCOS. Studies showed strong associations between overweight, body dissatisfaction, and disordered eating in PCOS. The etiologic development of EDs in PCOS remains unclear; however, psychological, metabolic, hypothalamic, and genetic factors are implicated. The prevalence of any ED in PCOS varied because of the use of different diagnostic and screening tools. Screening of all individuals with PCOS for EDs is recommended and high-quality studies on the prevalence, pathogenesis of specific EDs, relationship to comorbidities, and effective interventions to treat ED in those with PCOS are needed.
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Bulimia Nervosa , Diabetes Mellitus Tipo 2 , Transtornos da Alimentação e da Ingestão de Alimentos , Síndrome do Ovário Policístico , Feminino , Humanos , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/epidemiologia , Prevalência , Transtornos da Alimentação e da Ingestão de Alimentos/complicações , Transtornos da Alimentação e da Ingestão de Alimentos/epidemiologia , Bulimia Nervosa/epidemiologia , Bulimia Nervosa/psicologiaRESUMO
BACKGROUND: Polycystic Ovary Syndrome (PCOS) is the most common endocrine-metabolic disorder affecting health and quality of life of those affected across the lifespan. We currently have limited evidence-based data on the experience of those living with PCOS in the health care system including diagnosis, health concerns and disease management. The aim of this study was to assess the perceptions of health status, health care experience and disease management support in those affected by PCOS in Alberta, Canada. METHODS: An online questionnaire was completed via REDCap by individuals self-reporting a diagnosis of PCOS. Question categories included demographics, symptoms of PCOS and time to confirm a diagnosis, follow-up care, health concerns, and information resources. Descriptive statistics were used and thematic analyses was applied to open-response questions. RESULTS: Responses from 194 participants living in Canada (93% in Alberta) were included. The average age was 34 ± 8 years and BMI was 35 ± 9. Menstrual irregularity was identified in 84% of respondents as the first symptom noticed and the primary reason for seeking a medical consultation. A PCOS diagnosis occurred on average 4.3 years following awareness of first symptoms and required consultation with more than one primary care provider for 57% of respondents. Half (53%) of respondents reported not receiving a referral to specialists for follow-up care and 70% were not informed about long-term health morbidity such as diabetes or cardiovascular disease. Most respondents (82%) did their own research about PCOS using on-line sources, academic literature and advice from peer support. The participant themes from open questions for improving health care included more resources and support, increased and reliable information, better education and training for clinicians, timely diagnosis, prompt referrals to specialists, and generally more compassion and empathy to the challenges faced by those managing their disease. CONCLUSION: Our findings highlight the health concerns and challenges in health care for those with PCOS. In Alberta, Canada we have identified major gaps in health care including a timely diagnosis, follow up care and supports, and multidisciplinary care. This evidence-based data can be used to inform development of pathways to improve the health care experience in those affected by PCOS.
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Síndrome do Ovário Policístico , Feminino , Humanos , Adulto , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/diagnóstico , Síndrome do Ovário Policístico/terapia , Qualidade de Vida , Distúrbios Menstruais , Inquéritos e Questionários , Atenção à SaúdeRESUMO
This present investigation aimed at characterizing the biochemical potential and kinetic study of the protease isolated from kitchen wastewater bacteria, P2S1An. The enzymatic activity was optimum when incubated for 96 h, at 30°C and pH 9.0. The enzymatic activity of the purified protease (PrA) was 10.47-folds that of crude protease (S1). PrA was about 35 kDa in molecular weight. The broad pH and thermal stability, chelators, surfactants and solvent tolerance, and favorable thermodynamics suggested the potentiality of the extracted protease PrA. Thermal activity and stability were enhanced in presence of 1-mM Ca2+ ion at high temperatures. The protease was a serine one as its activity was completely diminished in presence of 1-mM PMSF. The Vmax , Km , and Kcat /Km suggested stability and catalytic efficiency of the protease. PrA hydrolyzes fish protein with 26.61 ± 0.16% of peptide bond cleavage after 240 min, comparable to Alcalase 2.4L (27.13 ± 0.31%). PRACTITIONER POINTS: A serine alkaline protease PrA was extracted from kitchen wastewater bacteria Bacillus tropicus Y14. Protease PrA showed significant activity and stability in a wide temperature and pH range. Protease showed great stability towards additives like metal ions, solvents, surfactants, polyols, and inhibitors. Kinetic study showed that the protease PrA had a prominent affinity and catalytic efficiency for the substrates. PrA hydrolysed fish proteins into short bioactive peptides which signify its potential in the formation of functional food ingredients.
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Serina Proteases , Águas Residuárias , Animais , Serina Proteases/química , Serina Proteases/metabolismo , Cinética , Endopeptidases/química , Endopeptidases/metabolismo , Proteínas de Bactérias , Bactérias/metabolismo , Temperatura , Tensoativos , Serina , Concentração de Íons de HidrogênioRESUMO
Context: Adrenal insufficiency (AI) is an uncommon, life-threatening disorder requiring lifelong treatment with steroid therapy and special attention to prevent adrenal crisis. Little is known about the prevalence of AI in Canada or healthcare utilization rates by these patients. Objective: We aimed to assess the prevalence and healthcare burden of AI in Alberta, Canada. Methods: This study used a population-based, retrospective administrative health data approach to identify patients with a diagnosis of AI over a 5-year period and evaluated emergency and outpatient healthcare utilization rates, steroid dispense records, and visit reasons. Results: The period prevalence of AI was 839 per million adults. Patients made an average of 2.3 and 17.8 visits per year in the emergency department and outpatient settings, respectively. This was 3 to 4 times as frequent as the average Albertan, and only 5% were coded as visits for AI. The majority of patients were dispensed glucocorticoid medications only. Conclusion: The prevalence of AI in Alberta is higher than published data in other locations. The frequency of visits suggests a significant healthcare burden and emphasizes the need for a strong understanding of this condition across all clinical settings. Our most concerning finding is that 94.3% of visits were not labeled with AI, even though many of the top presenting complaints were consistent with adrenal crisis. Several data limitations were discovered that suggest improvements in the standardization of data submission and coding can expand the yield of future studies using this method.
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CONTEXT: Women with polycystic ovary syndrome (PCOS) have increased incidence of atherogenic dyslipidemia and cardiovascular disease (CVD). Interventions targeting atherogenic dyslipidemia to reduce CVD risk are limited in women with PCOS. OBJECTIVE: This pilot study was conducted to determine the effect of 12 weeks of high dose fish oil (FO), metformin, and FO as an adjunct to metformin (FO-metformin) therapy on fasting and nonfasting plasma lipids and ApoB-remnants in young women with the metabolic syndrome (MetS) and PCOS. METHODS: In this open-label parallel pilot trial, women with MetS and PCOS (18-30 years of age) were randomized into 1 of 3 interventions: (1) FO; (2) metformin; and (3) FO-metformin. Plasma lipids and ApoB (48 and 100)-lipoproteins and triglycerides (TG) were measured in the fasted and postprandial state following a high-fat meal at baseline and postintervention. RESULTS: FO-metformin significantly lowered fasting plasma TG by >40% compared with FO and metformin treatments. Fasting plasma apoB48 was lowered 40% in FO-metformin and 15% in the FO groups from baseline to postintervention. ApoB48 area under the curve (ApoB48AUC), ApoB48 incremental AUC (ApoB48iAUC), ApoB100AUC, and ApoB100iAUC decreased in all groups from baseline to postintervention; however, these findings did not reach statistical significance. CONCLUSION: The findings of this pilot trial show that high dose FO and FO-metformin combination therapy tend to lower fasting and postprandial plasma TG and ApoB-lipoprotein remnants compared with metformin; however, the study is limited by small sample size. These results may be clinically significant in individuals with PCOS for management of atherogenic dyslipidemia.
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Healthy food trend is becoming popular these days fueling search for ingredients empowered by pharma-nutritional benefits. In contrast, numerous wild-growing mushrooms are traditionally cherished as health promoting gastronomies in India; although credibility of their effects has so far been limited. Hence the present study aimed to unveil a unique tribal cuisine, Russula alatoreticula, with nutritional, chemical and pharmacological relevance. The outcome demonstrated an excellent alimentary composition with carbohydrate and protein as prominent macronutrients in contrast to fat providing oleic acid (36.66%), linoleic acid (16.84%), palmitic acid (16.01%) and stearic acid (15.31%) indicative of profitable nutritive account. Conversely, ethanolic fraction enriched with phenolics (pyrogallol > cinnamic acid) presented effective antioxidant property in terms of radical scavenging, Fe2+ chelating and reducing power with EC50 ranging from 785 to 2500 µg/ml. Remarkable antibacterial activity was also noted against the tested microorganisms (MIC of 72.5-1560 µg/ml) preferentially targeting Gram-positive one. Besides treatment of the preparation rendered Hep3B proliferation as evident by phenotypic changes, cell cycle interference, reactive oxygen species generation, mitochondrial membrane potential reduction, DNA fragmentation, change in Bax/Bcl2 ratio and activation of caspase9 signifying induction of intrinsic mitochondrial pathway. Thus the study represents R. alatoreticula as a value-added bio-resource that could be featured in food and pharmaceutical industries for betterment of humankind.
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Flagellin is a protein, responsible for virulent activities of bacteria. The host cell surface receptor protein TLR5 is known to interact with flagellin in order to activate immune response. However, the underlying microscopic details of this immune response are still elusive. In this study, we report on conformational stability of flagellin of two different organisms known as fliC and flaD in bilayer with reference to water. We find that both the flagellin is conformationally more stable in bilayer than in water. We also observe that fliC-TLR5 and flaD-TLR5 complexes are conformationally stable when the extracellular domain of the protein binds to conserved D1 domain of both fliC and flaD, although the binding interface between fliC-TLR5 and flaD-TLR5 is not identical. Our studies suggest that this might lead to differences in coreceptor bindings involved in immune response and thus have potential application in pharmaceutical developments. AbbreviationsA2Aadenosine receptorDPPCdipalmitoyl phosphatidylcholineecdextracellular domainecl2extracellular loop 2eLRRextracellular Leucine rich repeat domainflaDflagellin of Vibrio choleraefliCflagellin of Salmonella typhimuriumHPVhyper-variableMDmolecular dynamicsRMSDroot means squared deviationTIRtoll-interleukin receptorTLR5toll like receptor 5VPAC1vasoactive intestinal peptide receptorCommunicated by Ramaswamy H. Sarma.
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Flagelina , Receptor 5 Toll-Like , Flagelina/metabolismo , Conformação Molecular , Ligação Proteica , Receptores de Superfície Celular , Receptor 5 Toll-Like/metabolismoRESUMO
The objective of the present study was to synthesize ω-3 polyunsaturated fatty acid esters of lutein and to evaluate if esterification can stabilize the both bioactive molecules. Both ω-3 polyunsaturated fatty acid and lutein are prone towards auto-oxidation in their free form. Free lutein extracted from the marigold petals was enzymatically esterified using Candida antarctica NS435 Lipase B, with the ω-3 long-chain polyunsaturated fatty acids. The lutein esters were purified, characterized and finally assessed for their protective role against oxidative degradation in bulk fish oil matrix. The antioxidative effect of these esters was compared with commercial antioxidants of natural origin, i.e., α-tocopherol and a synthetic antioxidant, i.e., tert-butylhydroquinone, at a dosage of 200 mg/L. Both free lutein and lutein-polyunsaturated fatty acid ester had significantly promoted the oxidative stability of bulk fish oil. But based on dose-response relationship, lutein-polyunsaturated fatty acid ester was found to be more efficient than free lutein, in protecting fish oil from secondary oxidation, thereby augmenting their shelf life. Given the high nutraceutical value, potent antioxidative potential and organic origin, it is only relevant to incorporate lutein esters as natural preservative and stabilizers in edible oils.
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Conformational changes in bio-molecular systems are fundamental to several biological processes. It is important to study changes in responses of underlying microscopic variables, like dihedral angles as conformational change takes place. We perform all-atom simulations and modelling via Langevin equation to illustrate the changes in structural and dynamic responses of dihedral angles of calcium ion binding residues of different proteins in metal ion free (apo) and bound (holo) states. The equilibrium distributions of dihedral angles in apo- and holo-states represent structural response. Our studies show the presence of dihedrals with multiple peaks (isomeric states) separated by barrier heights is more frequent in apo- than in holo-state. The relaxation time-scale of dihedral fluctuations is found to increase linearly with decreasing barrier height due to more frequent barrier re-crossing events. The slow kinetic response of the dihedrals also contributes to slowing down of macro-scale fluctuations, which may be useful to understand kinetics of various bio-molecular processes.
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Cálcio/metabolismo , Metaloproteínas/química , Metaloproteínas/metabolismo , Simulação de Dinâmica Molecular , Sítios de Ligação , Cálcio/química , Íons/química , Íons/metabolismo , Conformação ProteicaRESUMO
The physiological efficacy of nutraceuticals is dependent on their physicochemical nature and bioavailability across biological barriers. In the present work, effects of nano-sizing of emulsion-based delivery vehicle on the bioavailability of polyunsaturated fatty acids rich fish oil have been investigated via three-step experimental design; ex vivo rat everted intestinal sac model, cellular lipid uptake and the bioactivity in rat PBMCs. Nanoemulsion in comparison to the conventional emulsion has shown significant higher rate of uptake of polyunsaturated fatty acids in three segments of small intestine. The time-kinetics of such uptake was correlated with appearance of short-chain fatty acids in basal side of the everted sac. The bioavailability of the formulated fish oil and its inhibitory response against lipopolysaccharide-induced nitric oxide production in rat PBMCs were positively correlated. This formulation with nano-sized droplets can be utilized as smart delivery vehicles for designing oral therapies in future.
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Emulsões/química , Óleos de Peixe/farmacocinética , Nanoestruturas/química , Animais , Disponibilidade Biológica , Suplementos Nutricionais , Ácidos Docosa-Hexaenoicos/administração & dosagem , Ácidos Docosa-Hexaenoicos/farmacocinética , Ácido Eicosapentaenoico/administração & dosagem , Ácido Eicosapentaenoico/farmacocinética , Emulsões/farmacocinética , Ácidos Graxos Insaturados/administração & dosagem , Ácidos Graxos Insaturados/farmacocinética , Óleos de Peixe/administração & dosagem , Intestino Delgado/efeitos dos fármacos , Leucócitos Mononucleares/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Masculino , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Veículos Farmacêuticos/química , Veículos Farmacêuticos/farmacocinética , Ratos Sprague-DawleyRESUMO
Here, we study microscopic mechanism of complex formation between Ca2+-bound calmodulin (holoCaM) and Orai1 that regulates Ca2+-dependent inactivation process in eukaryotic cells. We compute conformational thermodynamic changes in holoCaM with respect to complex of Orai1 bound to C-terminal domain of holoCaM using histograms of dihedral angles of the proteins over trajectories from molecular dynamics simulations. Our analysis shows that the N-terminal domain residues L4, T5, Q41, N42, T44 and E67 of holoCaM get destabilized and disordered due to Orai1 binding to C-terminal domain of calmodulin affect the N-terminal domain residues. Among these residues, polar T44, having maximum destabilization and disorder via backbone fluctuations, shows the largest change in solvent exposure. This suggests that N-terminal domain is allosterically regulated via T44 by the binding of Orai1 to the C-terminal domain.
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Calmodulina/química , Simulação de Dinâmica Molecular , Proteína ORAI1/química , Conformação Proteica , Termodinâmica , Regulação Alostérica , Calmodulina/metabolismo , Simulação de Acoplamento Molecular , Proteína ORAI1/metabolismo , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Relação Estrutura-AtividadeRESUMO
We study the motion of Zn^{2+} in the presence of ubiquitin by all-atom molecular-dynamics simulations. We observe that unlike normal diffusive liquid, metal ions show an exponential tail in the self-van Hove function (self-vHf). Moreover, the metal ions are trapped strongly by acidic residues which form a binding pocket over the protein surface. The exponential tail disappears by mutation of trapping residues, suggesting that the tail appears due to trapped motion of the ions. The mean-squared displacements, however, in all the cases show linear dependence on time. Our model establishes that ligand binding generically results in an exponential tail of self-vHf. The self-vHf may give an approach to find binding pockets over a protein surface.
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Proteínas/metabolismo , Ligantes , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica , Proteínas/química , Ubiquitina/química , Ubiquitina/metabolismo , Zinco/metabolismoRESUMO
Anion binding CαNN motif is found in functionally important regions of protein structures. This motif based only on backbone atoms from three adjacent residues, recognizes free sulphate or phosphate ion as well as phosphate groups in nucleotides and in a variety of cofactors. The mode of anion recognition and microscopic picture of binding interaction remains unclear. Here we perform self-consistent quantum chemical calculations considering sulphate and phosphate bound CαNN motif fragments from crystal structures of functional proteins in order to figure out microscopic basis of anion recognition. Our calculations indicate that stability and preference of the anion in the motif depends on the sequence of the motif. The stabilization energy is larger in case of polar residue containing motif fragment. Nitrogen atom of the polar residue of motif mainly participates in the coordination at the lowest energy levels. Anion replacement decreases stabilization energy along with coordination between motif atoms and oxygen atoms of anion shifted to higher energies, suggesting preference of the motif residues to specific anion. Our analysis may be helpful to understand microscopic basis of interaction between proteins and ionic species.
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Modelos Moleculares , Proteínas/química , Teoria Quântica , Motivos de Aminoácidos , Ânions/química , Ligação de Hidrogênio , Nitrogênio/química , Oxigênio/química , TermodinâmicaRESUMO
Molecular understanding of bio-macromolecular binding is a challenging task due to large sizes of the molecules and presence of variety of interactions. Here, we study the molecular mechanism of calmodulin (CaM) binding to Orai1 that regulates Ca2+-dependent inactivation process in eukaryotic cells. Although experimental observations indicate that Orai1 binds to the C-terminal of Ca2+-loaded CaM, it is not decisive if N-domain of CaM interacts with Orai1. We address the issue of interaction of different domains of CaM with Orai1 using conformational thermodynamic changes, computed from histograms of dihedral angles over simulated trajectories of CaM, CaM-binding domain of Orai1 and complexes of CaM with Orai1. The changes for all residues of both C and N terminal domains of CaM upon Orai1 binding are compared. Our analysis shows that Orai1binds to both C-terminal and N-terminal domains of CaM, indicating 1:2 stoichiometry. The Orai1 binding to N-terminal domain of CaM is less stable than that to the C-terminal domain. The binding residues are primarily hydrophobic. These observations are in qualitative agreement to the experiments. The conformational thermodynamic changes thus provide a useful computational tool to provide atomic details of interactions in bio-macromolecular binding.
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Calmodulina/química , Complexos Multiproteicos/química , Proteína ORAI1/química , Termodinâmica , Sequência de Aminoácidos/genética , Cálcio/metabolismo , Calmodulina/genética , Humanos , Interações Hidrofóbicas e Hidrofílicas , Simulação de Dinâmica Molecular , Complexos Multiproteicos/genética , Proteína ORAI1/genética , Ligação Proteica/genética , Conformação ProteicaRESUMO
We perform molecular dynamics simulation studies on interaction between bacterial proteins: an outer-membrane protein STY3179 and a yfdX protein STY3178 of Salmonella Typhi. STY3179 has been found to be involved in bacterial adhesion and invasion. STY3178 is recently biophysically characterized. It is a soluble protein having antibiotic binding and chaperon activity capabilities. These two proteins co-occur and are from neighboring gene in Salmonella Typhi-occurrence of homologs of both STY3178 and STY3179 are identified in many Gram-negative bacteria. We show using homology modeling, docking followed by molecular dynamics simulation that they can form a stable complex. STY3178 belongs to aqueous phase, while the beta barrel portion of STY3179 remains buried in DPPC bilayer with extra-cellular loops exposed to water. To understand the molecular basis of interaction between STY3178 and STY3179, we compute the conformational thermodynamics which indicate that these two proteins interact through polar and acidic residues belonging to their interfacial region. Conformational thermodynamics results further reveal instability of certain residues in extra-cellular loops of STY3179 upon complexation with STY3178 which is an indication for binding with host cell protein laminin.
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Proteínas de Bactérias/química , Simulação de Dinâmica Molecular , Conformação Proteica , Termodinâmica , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Modelos Moleculares , Ligação Proteica , Salmonella typhi/metabolismo , Salmonella typhi/patogenicidade , VirulênciaRESUMO
Among different ligand binding motifs, anion binding Cα NN motif consisting of peptide backbone atoms of three consecutive residues are observed to be important for recognition of free anions, like sulphate or biphosphate and participate in different key functions. Here we study the interaction of sulphate and biphosphate with Cα NN motif present in different proteins. Instead of total protein, a peptide fragment has been studied keeping Cα NN motif flanked in between other residues. We use classical force field based molecular dynamics simulations to understand the stability of this motif. Our data indicate fluctuations in conformational preferences of the motif residues in absence of the anion. The anion gives stability to one of these conformations. However, the anion induced conformational preferences are highly sequence dependent and specific to the type of anion. In particular, the polar residues are more favourable compared to the other residues for recognising the anion.
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Ânions/química , Fragmentos de Peptídeos/química , Proteínas/química , Motivos de Aminoácidos , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Conformação Proteica , Estrutura Secundária de Proteína , TermodinâmicaRESUMO
Octacosanol is a lesser known nutraceutical with the potential for treatment of several inflammatory diseases, high cholesterol, Parkinson's symptoms and tumour growth along with the capacity to improve athletic performance. But its lipophilicity and large structure inhibits extended solubility in water resulting in poor absorption and a low bioavailability. In the present work, sodium salt of octacosyl sulfate was synthesized. It displayed improved water solubility. Its nanocrystals, synthesized by means of nanoprecipitation technique, enhanced diffusion velocity, antioxidant capacity, shelf-life, penetrability and bioavailability. Particle size of the nanocrystals ranged between 197 and 220nm. Both modified octacosanol and its nanocrystals displayed maximum lipid peroxidation activities at a concentration 1000ppm, but nanocrystals demonstrated higher prevention. From freeze-thaw cycles it was evident that normal octacosanol crystals were far more prone to temperature variations than the nanocrystals. A pronounced increase in release/diffusion rate and bioavailability was observed for the nanocrystals of the modified octacosanol. In vitro release kinetics, bioavailability and bioequivalence were studied. Relative bioavailability for gastric passage and pancreatic passage of nanocrystals was 2.58 times and 1.81 times that of normal crystals respectively. Furthermore the nanocrystals displayed a superior in vitro release rate, while following a non-Fickian mode.