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1.
Proc Natl Acad Sci U S A ; 121(21): e2321512121, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38748582

RESUMO

The outer membrane (OM) of didermic gram-negative bacteria is essential for growth, maintenance of cellular integrity, and innate resistance to many antimicrobials. Its asymmetric lipid distribution, with phospholipids in the inner leaflet and lipopolysaccharides (LPS) in the outer leaflet, is required for these functions. Lpt proteins form a transenvelope bridge that transports newly synthesized LPS from the inner membrane (IM) to OM, but how the bulk of phospholipids are transported between these membranes is poorly understood. Recently, three members of the AsmA-like protein family, TamB, YhdP, and YdbH, were shown to be functionally redundant and were proposed to transport phospholipids between IM and OM in Escherichia coli. These proteins belong to the repeating ß-groove superfamily, which includes eukaryotic lipid-transfer proteins that mediate phospholipid transport between organelles at contact sites. Here, we show that the IM-anchored YdbH protein interacts with the OM lipoprotein YnbE to form a functional protein bridge between the IM and OM in E. coli. Based on AlphaFold-Multimer predictions, genetic data, and in vivo site-directed cross-linking, we propose that YnbE interacts with YdbH through ß-strand augmentation to extend the continuous hydrophobic ß-groove of YdbH that is thought to shield acyl chains of phospholipids as they travel through the aqueous intermembrane periplasmic compartment. Our data also suggest that the periplasmic protein YdbL prevents extensive amyloid-like multimerization of YnbE in cells. We, therefore, propose that YdbL has a chaperone-like function that prevents uncontrolled runaway multimerization of YnbE to ensure the proper formation of the YdbH-YnbE intermembrane bridge.


Assuntos
Proteínas da Membrana Bacteriana Externa , Membrana Externa Bacteriana , Proteínas de Escherichia coli , Escherichia coli , Homeostase , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Membrana Externa Bacteriana/metabolismo , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas da Membrana Bacteriana Externa/genética , Fosfolipídeos/metabolismo , Lipopolissacarídeos/metabolismo , Lipoproteínas/metabolismo , Membrana Celular/metabolismo
2.
Res Nurs Health ; 47(1): 82-92, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38095101

RESUMO

Recruitment of residents for research from long-term care settings is known to be difficult. The purpose of this study was to summarize the effectiveness and cost in terms of time and dollars of recruitment methods for a cluster-randomized controlled clinical trial conducted in long-term care settings. This study was a retrospective, exploratory, descriptive analysis of recruitment data. After recruitment of 15 independent and assisted living communities, residents at each site were recruited to participate in the study using combinations of 12 different recruitment methods. Recruitment methods, time spent screening, and enrollment data were collected. Recruitment data were analyzed at the levels of site, research staff member, and participant. Over the study period, 279 older adults were screened and 172 enrolled from the 15 sites. Many participants were cognitively impaired. Research staff spent 39-89 h recruiting at each site and utilized an average of four different recruitment methods per site. Introductions of participants by site contacts yielded the most consented participants compared to other recruitment methods. Sites that had a dedicated recruiter utilized more recruiting methods and enrolled more participants than those without a dedicated recruiter. The cost of recruiting averaged $1490 per site and $93-$258 per enrollee (mean $144, standard deviation $58), but was more costly in larger facilities. Recruitment of older adults from long-term care communities requires multiple methods of recruitment, skilled recruitment staff, and trust with the staff and potential participants.


Assuntos
Assistência de Longa Duração , Seleção de Pacientes , Idoso , Humanos , Coleta de Dados , Estudos Retrospectivos , Ensaios Clínicos Controlados Aleatórios como Assunto
3.
PLoS Comput Biol ; 18(10): e1010613, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36228001

RESUMO

Screening for novel antibacterial compounds in small molecule libraries has a low success rate. We applied machine learning (ML)-based virtual screening for antibacterial activity and evaluated its predictive power by experimental validation. We first binarized 29,537 compounds according to their growth inhibitory activity (hit rate 0.87%) against the antibiotic-resistant bacterium Burkholderia cenocepacia and described their molecular features with a directed-message passing neural network (D-MPNN). Then, we used the data to train an ML model that achieved a receiver operating characteristic (ROC) score of 0.823 on the test set. Finally, we predicted antibacterial activity in virtual libraries corresponding to 1,614 compounds from the Food and Drug Administration (FDA)-approved list and 224,205 natural products. Hit rates of 26% and 12%, respectively, were obtained when we tested the top-ranked predicted compounds for growth inhibitory activity against B. cenocepacia, which represents at least a 14-fold increase from the previous hit rate. In addition, more than 51% of the predicted antibacterial natural compounds inhibited ESKAPE pathogens showing that predictions expand beyond the organism-specific dataset to a broad range of bacteria. Overall, the developed ML approach can be used for compound prioritization before screening, increasing the typical hit rate of drug discovery.


Assuntos
Descoberta de Drogas , Bibliotecas de Moléculas Pequenas , Estados Unidos , Bibliotecas de Moléculas Pequenas/farmacologia , Aprendizado de Máquina , Antibacterianos/farmacologia
4.
Aust N Z J Obstet Gynaecol ; 63(4): 599-602, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37200477

RESUMO

Uterine transplantation (UT) is an emerging medical treatment for women affected by absolute uterine factor infertility (AUFI). To date there have been over 90 documented cases of UT performed worldwide, with over 50 live births. UT allows women affected by AUFI the opportunity to carry and deliver a childd. The Royal Prince Alfred Hospital (RPAH) introduced a UT study in 2019; however, due to the impacts of the COVID pandemic the study was placed on hold for two years. In February 2023, RPAH performed the centre's first UT from a living unrelated donor to a 25-year-old woman with Mayer-Rokitansky-Küster-Hauser syndrome. The donor and recipient surgeries were uncomplicated and both are recovering well in the early post-operative period.


Assuntos
Transtornos 46, XX do Desenvolvimento Sexual , COVID-19 , Anormalidades Congênitas , Infertilidade Feminina , Feminino , Humanos , Adulto , Útero/cirurgia , Infertilidade Feminina/etiologia , Infertilidade Feminina/cirurgia , Hospitais , Transtornos 46, XX do Desenvolvimento Sexual/complicações , Transtornos 46, XX do Desenvolvimento Sexual/cirurgia
5.
Nurs Educ Perspect ; 2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37043459

RESUMO

ABSTRACT: With the implementation of Next Generation NCLEX (NGN), many prelicensure nurse faculty feel unprepared to create examination items in the formats proposed. These formats are designed to meaningfully evaluate clinical judgment while providing learners experience with the NGN assessment format prior to their sitting for the licensure examination. This article presents one program's pilot of NGN-style exam items in three clinical courses. Resources created for faculty to successfully implement the pilot items, outcomes of the pilot, and future plans for full implementation are discussed.

6.
Nurs Educ Perspect ; 2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37948042

RESUMO

ABSTRACT: Competence in interprofessional collaboration is essential for safe patient outcomes. This study examined the impact of an interprofessional telehealth pharmacology simulation on prelicensure nursing and pharmacy students' perceptions of interprofessional roles. A pretest-posttest design was used to compare participants' perceptions of interprofessional roles prior to and following the simulation. Data were collected using the Interdisciplinary Education Perception Scale (IEPS). Paired-samples t-tests showed statistically significant increases in scores for both the full IEPS (n = 99) and two subscales, Competency and Autonomy (n = 99) and Perception of Actual Cooperation (n = 99). Nurse educators should provide regular interprofessional experiences to foster learners' competence in interprofessional collaboration and communication.

7.
BMC Bioinformatics ; 23(Suppl 4): 132, 2022 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-35428173

RESUMO

BACKGROUND: Converting molecules into computer-interpretable features with rich molecular information is a core problem of data-driven machine learning applications in chemical and drug-related tasks. Generally speaking, there are global and local features to represent a given molecule. As most algorithms have been developed based on one type of feature, a remaining bottleneck is to combine both feature sets for advanced molecule-based machine learning analysis. Here, we explored a novel analytical framework to make embeddings of the molecular features and apply them in the clustering of a large number of small molecules. RESULTS: In this novel framework, we first introduced a principal component analysis method encoding the molecule-specific atom and bond information. We then used a variational autoencoder (AE)-based method to make embeddings of the global chemical properties and the local atom and bond features. Next, using the embeddings from the encoded local and global features, we implemented and compared several unsupervised clustering algorithms to group the molecule-specific embeddings. The number of clusters was treated as a hyper-parameter and determined by the Silhouette method. Finally, we evaluated the corresponding results using three internal indices. Applying the analysis framework to a large chemical library of more than 47,000 molecules, we successfully identified 50 molecular clusters using the K-means method with 32 embeddings based on the AE method. We visualized the clustering result via t-SNE for the overall distribution of molecules and the similarity maps for the structural analysis of randomly selected cluster-specific molecules. CONCLUSIONS: This study developed a novel analytical framework that comprises a feature engineering scheme for molecule-specific atomic and bonding features and a deep learning-based embedding strategy for different molecular features. By applying the identified embeddings, we show their usefulness for clustering a large molecule dataset. Our novel analytic algorithms can be applied to any virtual library of chemical compounds with diverse molecular structures. Hence, these tools have the potential of optimizing drug discovery, as they can decrease the number of compounds to be screened in any drug screening campaign.


Assuntos
Algoritmos , Análise por Conglomerados , Análise de Componente Principal
8.
Org Biomol Chem ; 20(29): 5730-5734, 2022 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-35852820

RESUMO

Employing a combination of mechanistic, kinetic and computational studies we have examined the mechanism of the TBD-catalyzed carboxylative cyclization of indole derivatives. Our studies provide insight into the role of the guanidine superbase TBD in catalyzing C-C bond formation between indole derivatives and CO2.


Assuntos
Guanidinas , Indóis , Catálise , Ciclização , Guanidina/química
9.
Transpl Infect Dis ; 24(1): e13758, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34762768

RESUMO

BACKGROUND AND AIM: Data are limited on whether Clostridioides difficile infection (CDI) in the first year after liver transplantation (LT) is associated with increased mortality. In an Australian setting without hypervirulent strain of C. difficile we investigated the prevalence, risk factors, and patient survival associated with CDI in LT. METHODS: Consecutive patients who underwent deceased-donor LT from 2007 to 2017 were studied retrospectively. Prevalence and long-term outcomes of LT recipients with and without CDI were examined in the entire LT cohort. A case-control study was performed to investigate risk factors associated with CDI. RESULTS: Six hundred and forty-nine patients underwent LT, of which 32 (4.9%) were diagnosed with CDI within the first 12 months post-LT. There was no difference in patient survival in the overall LT cohort on Kaplan-Meier analysis when stratified by CDI status (log-rank test, p = .08). Furthermore, age was the only predictor of mortality on Cox regression (hazard ratio (HR) 1.06, 95% confidence interval (CI) 1.00-1.13, p = .03). On multivariable logistic regression, rifaximin pre-LT reduced risk (odds ratio (OR) 0.22, 95% CI 0.65-0.74, p = .01) whereas antibiotics pre-LT (OR 7.02, 95% CI 1.26-39.01, p = .03) and length of hospital stay after LT (OR 1.03, 95% CI 1.01-1.06, p = .02) were associated with increased risk of CDI. CONCLUSIONS: Within the local setting of our study, CDI within 12 months post-LT is of low severity, associated with pre-LT antibiotic exposure and longer hospital stay but no survival impact after LT. Rifaximin use pre-LT reduced the risk of CDI post-LT.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Transplante de Fígado , Austrália/epidemiologia , Estudos de Casos e Controles , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/epidemiologia , Humanos , Transplante de Fígado/efeitos adversos , Prevalência , Estudos Retrospectivos , Fatores de Risco , Transplantados
10.
J Paediatr Child Health ; 58(4): 611-617, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34704652

RESUMO

AIM: We aimed to describe health-related out-of-pocket (OOP) expenses incurred by Australian families living with children with chronic and complex diseases. METHODS: A prospective pilot study of OOP expenses in families with children with tuberous sclerosis (TS) or mitochondrial disorders (MD) in 2016-2017. An initial survey assessed the family's financial situation, child's health functioning and estimated previous 6 months' and lifetime OOP expenses. Thereafter, families completed a survey each month for 6 months, prospectively tracking OOP expenses. RESULTS: Initial surveys were completed by 13 families with 15 children; median age 7 years (range: 1-12); 5 with MD, 10 with TS. All families reported OOP expenses: 38% paid $2000 per annum, more than double the annual per-capita OOP costs reported for Australia by the Organisation for Economic Co-operation and Development. Eight families estimated $5000-$25 000 in OOP expenses over their child's lifetime and 62% of mothers reduced or stopped work due to caring responsibilities. Eleven families paid annual private health insurance premiums of $2000-$5122, but 72% said this was poor value-for-money. Prospective tracking by eight families (9 children) identified the median OOP expenditure was $863 (range $55-$1398) per family for 6 months. OOP spending was associated with visits to allied health professionals, non-prescription medicines, special foods, supplements and disposable items. Eight families paid for 91 prescription medications over 6 months. CONCLUSION: All families caring for children with TS or MD reported OOP expenses. A larger study is needed to explore the affordability of health care for children living with a broader range of chronic diseases.


Assuntos
Doenças Mitocondriais , Esclerose Tuberosa , Austrália , Criança , Pré-Escolar , Gastos em Saúde , Humanos , Lactente , Projetos Piloto , Estudos Prospectivos , Doenças Raras
11.
Genomics ; 113(6): 3978-3988, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34619342

RESUMO

The common green bottle blow fly Lucilia sericata (family, Calliphoridae) is widely used for maggot debridement therapy, which involves the application of sterile maggots to wounds. The larval excretions and secretions are important for consuming necrotic tissue and inhibiting bacterial growth in wounds of patients. Lucilia sericata is also of importance as a pest of sheep and in forensic studies to estimate a postmortem interval. Here we report the assembly of a 565.3 Mb genome from long read PacBio DNA sequencing of genomic DNA. The genome contains 14,704 predicted protein coding genes and 1709 non-coding genes. Targeted annotation and transcriptional analyses identified genes that are highly expressed in the larval salivary glands (secretions) and Malpighian tubules (excretions) under normal growth conditions and following heat stress. The genomic resources will underpin future genetic studies and in development of engineered strains for genetic control of L. sericata and for biotechnology-enhanced maggot therapy.


Assuntos
Calliphoridae , Dípteros , Animais , Desbridamento , Dípteros/genética , Humanos , Larva/genética , Larva/metabolismo , Ovinos/genética , Transcriptoma
12.
J Org Chem ; 86(17): 11673-11682, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34375521

RESUMO

Heteroaromatic aldehydes have recently received a lot of attention as a scaffold for aminocatalytic functionalization as they allow for the construction of remote stereocenters and highly complex heterocyclic compounds. In this paper, we employ computational methods (M06-2X/cc-pVTZ//M06-2X/6-31 + G(d,p) and MP2/cc-pVTZ//M06-2X/6-31 + G(d,p)) to examine the abilities of secondary amines to activate several model heteroaromatic aldehydes by promoting loss of aromaticity and formation of the reactive trienamine intermediate. The hyperhomodesmotic equations used to assess the energy penalty for dearomatization show that the formation of the iminium ion decreases the energy cost for dearomatization, especially when X = O and S. Furthermore, we also investigated the role that the catalyst and heteroatom may have on the orbital coefficients of the various positions of the trienamine intermediary in order to better understand and/or predict the regioselectivity these systems may showcase. Synergistic effects between the catalyst and the heteroatom of the aromatic ring were observed to increase electron density at the most remote positions of several of the model systems studied.

13.
Org Biomol Chem ; 19(2): 399-405, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33300539

RESUMO

Keto-substituted 1,2-cyclohexadienes were generated by base-mediated (KOt-Bu) elimination, and found to dimerize via an unprecedented formal hetero-Diels-Alder process, followed by hydration. These highly reactive cyclic allene intermediates were also trapped in Diels-Alder reactions by furan, 2,5-dimethylfuran, or diphenylisobenzofuran to afford cycloadducts with high regio- and diastereoselectivity, and could also be intercepted in a hetero-Diels-Alder process with enamine dienophiles. Endo/exo stereochemistry was unambiguously determined via X-ray crystallography in the case of nitrile-substituted 1,2-cyclohexadiene. DFT calculations indicate that the novel hetero-Diels-Alder processes observed with these allenes occur via a concerted asynchronous cycloaddition mechanism.

14.
Public Health Nurs ; 38(3): 449-458, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33103278

RESUMO

OBJECTIVE: Aims of this study were to identify the Association of Community/Public Health Nursing Educators members' demographics, educational preparation, and research competencies; and, to complete a strengths, weaknesses, opportunities, and threats (SWOT) analysis. METHODS: A descriptive-correlational design was employed. Primary data collection was via electronic survey. Authors developed a survey focusing on demographics and aligning Benner's theory with research skills/experience. SWOT and gap analyses were performed. RESULTS: A 27.2% response rate (N = 352) revealed a lack of diversity among 70% doctorally prepared membership, perceived competence with interprofessional collaboration (80%), and applying research to practice (80%). Doctorally prepared members reported experience using longitudinal designs (p = .05). PhD-prepared members reported experience using psychometrics and evaluations (p = .05). SWOT revealed a lack of service engagement. Gap analysis offered solutions to execute strategic goals. CONCLUSIONS: Association of Community/Public Health Nursing Educators may enhance future direction by advancing member diversity, professional development, collaborative scholarship, and mentoring.


Assuntos
Enfermagem em Saúde Pública , Humanos
15.
J Gerontol Nurs ; 47(1): 21-27, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33377981

RESUMO

The purpose of the current study was to determine if persons with Alzheimer's disease (AD) or mild cognitive impairment (MCI) due to AD reported awareness of driving ability and made self-regulatory changes to the same degree as older adults without AD. Driving awareness and behaviors were collected using a self-report survey. Results of the AD/MCI group were compared to a similarly aged control group. Results showed that persons with AD/MCI reported less confidence in their driving ability and worried about getting lost more often than the control group. In addition, they were more likely to have stopped driving. The AD/MCI group reported that they avoided driving in unfamiliar situations, drove less often, and drove with another person significantly more than the control group. The results give evidence that persons within the early stage of AD may have self-awareness of their driving ability and self-regulate their driving to enhance safety. [Journal of Gerontological Nursing, 47(1), 21-27.].


Assuntos
Doença de Alzheimer , Condução de Veículo , Disfunção Cognitiva , Autocontrole , Idoso , Humanos , Testes Neuropsicológicos , Inquéritos e Questionários
16.
J Child Sex Abus ; 30(1): 21-40, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30507359

RESUMO

This study examined the perpetration of sexual violence within the institutional setting of primary schools in Liberia using secondary analysis of data collected from 811 Liberian school aged participants (298 girls and 513 boys). The study looked specifically at the perpetration of: 1) sexual violation, 2) transactional sex, and 3) sexual coercion. Sexual violation was the most common form of sexual violence experienced, followed by sexual coercion, and then transactional sex. Findings showed statistically significant differences in experiences of transactional sex and sexual coercion, with girls more likely to experience both forms of violence. Further, girls were more likely to experience sexual abuse by a teacher and religious figure. Perpetration by teachers, school staff, and religious figures were all linked to transactional sex. Results showed that transactional sex was most highly statistically significantly associated with teachers while perpetration by a religious figure was statistically significantly associated with sexual coercion. Girls had three times of the odds of experiencing transactional sex and coercion. We conclude that there is a need for interventions to prevent sexual abuse from occurring in educational institutions. In particular, there is a need for protective mechanisms addressing the transactional nature of abuse with teachers and school staff.


Assuntos
Abuso Sexual na Infância/estatística & dados numéricos , Vítimas de Crime/estatística & dados numéricos , Instituições Acadêmicas , Estudantes/estatística & dados numéricos , Criança , Abuso Sexual na Infância/classificação , Vítimas de Crime/classificação , Feminino , Humanos , Libéria/epidemiologia , Masculino , Inquéritos e Questionários
17.
Beilstein J Org Chem ; 17: 439-460, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33727970

RESUMO

Due to the heterocyclic structure and distinct conformational profile, proline is unique in the repertoire of the 20 amino acids coded into proteins. Here, we summarize the biochemical work on the replacement of proline with (4R)- and (4S)-fluoroproline as well as 4,4-difluoroproline in proteins done mainly in the last two decades. We first recapitulate the complex position and biochemical fate of proline in the biochemistry of a cell, discuss the physicochemical properties of fluoroprolines, and overview the attempts to use these amino acids as proline replacements in studies of protein production and folding. Fluorinated proline replacements are able to elevate the protein expression speed and yields and improve the thermodynamic and kinetic folding profiles of individual proteins. In this context, fluoroprolines can be viewed as useful tools in the biotechnological toolbox. As a prospect, we envision that proteome-wide proline-to-fluoroproline substitutions could be possible. We suggest a hypothetical scenario for the use of laboratory evolutionary methods with fluoroprolines as a suitable vehicle to introduce fluorine into living cells. This approach may enable creation of synthetic cells endowed with artificial biodiversity, containing fluorine as a bioelement.

18.
Mol Genet Genomics ; 295(2): 287-298, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31720776

RESUMO

For genetic approaches for controlling insect pests such as the sterile insect technique (SIT), it is advantageous to release only males as females are ineffective as control agents and they consume about 50% of the diet. Here we developed tetracycline-repressible Lucilia cuprina transgenic strains in which adult females were fully fertile and viable on a diet that lacked tetracycline and all of their female offspring died at the embryo stage. The transgenic strains are an improvement over the strains we developed previously, which had the disadvantage that adult females on diet without tetracycline were sterile and died prematurely. This was possibly due to the low level expression of the effector gene in ovaries. In the strains developed in this study, the early promoters from L. cuprina nullo or Cochliomyia macellaria CG14427 genes were used to drive the tetracycline transactivator (tTA) expression in the early embryo. In the absence of tetracycline, tTA activates expression of the proapoptotic gene Lshid which contains a female-specific intron. Consequently, only females produce active HID protein and die at the embryo stage. Crossing the tTA-expressing driver lines with an RFPex reporter line confirmed that there was no expression of the effector gene in the ovary. These new embryonic L. cuprina transgenic sexing strains hold great promise for genetic control programs and the system reported here might also be transferable to other major calliphorid livestock pests such as the New World screwworm, Cochliomyia hominivorax.


Assuntos
Dípteros/genética , Proteínas de Insetos/genética , Controle Biológico de Vetores , Ovinos/parasitologia , Animais , Animais Geneticamente Modificados , Austrália , Dípteros/patogenicidade , Desenvolvimento Embrionário/genética , Feminino , Masculino , Regiões Promotoras Genéticas , Ovinos/genética , Tetraciclina/biossíntese
19.
J Comput Chem ; 41(5): 472-481, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31652004

RESUMO

Cation-π interactions play important roles in molecular recognition and in the stability and function of proteins. However, accurate description of the structure and energetics of cation-π interactions presents a challenge to both additive and polarizable force fields, which are rarely designed to account for the complexation of charged groups with aromatic moieties. We calibrate the Drude polarizable force field for complexes of alkali metal ions (Li+ , Na+ , K+ , Rb+ , Cs+ ), ammonium (NH4+ ), tetramethylammonium (TMA+ ), and tetraethylammonium (TEA+ ) with aromatic amino acid side chain model compounds (benzene, toluene, 4-methylphenol, 3-methylindole) using high-level ab initio quantum chemical properties of these complexes. Molecular dynamics simulations reveal that cation-π complexes of the hard and tightly coordinated Li+ and Na+ ions are not stable in water but that larger ions form stable complexes, with binding free energies ranging between -0.8 and -2.9 kcal/mol. Like in gas phase, all complexes at equilibrium adopt an "en-face" complexation mode in water. The optimized Drude polarizable model provides an accurate description of the cation-π interactions involving small ions and proteins. © 2019 Wiley Periodicals, Inc.


Assuntos
Aminoácidos Aromáticos/química , Teoria da Densidade Funcional , Metais Alcalinos/química , Compostos de Amônio Quaternário/química , Íons/química
20.
Chembiochem ; 21(8): 1150-1154, 2020 04 17.
Artigo em Inglês | MEDLINE | ID: mdl-31702879

RESUMO

The activation of toll-like receptors (TLRs) plays important roles in the immune response. The ability to control the activities of TLRs could be usable as a switch for immune response. Here we have rationally designed and synthesized a photoswitchable Pam3 CSK4 derivative-P10-to control the activation of TLR1/2. The ground-state trans-P10 was able to stimulate and activate antigen-presenting cells (APCs) by promoting TLR1/2 heterodimerization. However, cis-P10, derived from UV irradiation of trans-P10, reduced the activities of APCs by impeding the TLR1/2 heterodimerization. In the absence of UV radiation, the cis-P10 slowly returned to its ground trans state, restoring the activities of the APCs stimulation. Our results indicated that optical control of TLR1/2 heterodimerization mediated by the photoswitchable P10 offers the potential to regulate immune activation and inflammation.


Assuntos
Células Apresentadoras de Antígenos/imunologia , Imunidade/imunologia , Lipopeptídeos/farmacologia , Multimerização Proteica , Receptor 1 Toll-Like/agonistas , Receptor 2 Toll-Like/agonistas , Raios Ultravioleta , Animais , Células Apresentadoras de Antígenos/metabolismo , Humanos , Camundongos , Células RAW 264.7 , Transdução de Sinais , Células THP-1 , Receptor 1 Toll-Like/química , Receptor 2 Toll-Like/química
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