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1.
Int J Bioprint ; 9(1): 647, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36844238

RESUMO

336MXenes, as highly electronegative and conductive two-dimensional nanomaterials, are extensively studied for their use in sensors and flexible electronics. In this study, near-field electrospinning was used to prepare a new poly(vinylidene difluoride) (PVDF)/Ag nanoparticle (AgNP)/MXene composite nanofiber film as a self-powered flexible human motion-sensing device. The composite film displayed highly piezoelectric properties with the presence of MXene. Scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy revealed that the intercalated MXene in the composite nanofibers was evenly spread out, which not only prevented the aggregation of MXene but also enabled the composite materials to form self-reduced AgNPs. The prepared PVDF/AgNP/MXene fibers displayed exceptional stability and excellent output performance, enabling their use for energy harvesting and powering light-emitting diodes. The doping of MXene/AgNPs increased the electrical conductivity of the PVDF material, improved its piezoelectric properties, and enhanced the piezoelectric constant of PVDF piezoelectric fibers, thereby allowing the production of flexible, sustainable, wearable, and self-powered electrical devices.

2.
Sci Rep ; 13(1): 296, 2023 01 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609424

RESUMO

Both current live, attenuated, and killed virus vaccines for bovine viral diarrhea virus (BVDV) have their limitations. Here, we report the development of a BVDV subunit vaccine by (i) the expression of a secreted form of a recombinant E2 glycoprotein using BHK21 cells and (ii) determination of the immune responses in mice. The E2 glycoprotein was modified by deletion of the C-terminal transmembrane anchor domain and fusion to a V5 epitope tag. This allowed detection using anti-V5 monoclonal antibodies together with simple purification of the expressed, secreted, form of E2 from the cell media. Furthermore, we genetically fused green fluorescent protein (GFP) linked to E2 via a Thosea asigna virus 2A (T2A) ribosome skipping sequence thereby creating a self-processing polyprotein [GFP-T2A-BVDV-E2trunk-V5], producing discrete [GFP-T2A] and [E2trunk-V5] translation products: GFP fluorescence acts, therefore, as a surrogate marker of E2 expression, BALB/c mice were inoculated with [E2trunk-V5] purified from cell media and both humoral and cellular immune responses were observed. Our antigen expression system provides, therefore, both (i) a simple antigen purification protocol together with (ii) a feasible strategy for further, large-scale, production of vaccines.


Assuntos
Vírus da Diarreia Viral Bovina , Vacinas Virais , Animais , Camundongos , Proteínas do Envelope Viral , Anticorpos Antivirais , Glicoproteínas , Proteínas Recombinantes , Vacinas de Subunidades Antigênicas , Diarreia
3.
Nurse Educ Today ; 119: 105601, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36244254

RESUMO

BACKGROUND: Given rapidly aging societies worldwide, improving the quality of long-term care through the cultivation of immense nursing assistants is critical. Accordingly, developing a satisfactory learning model to improve the learning outcomes of nursing assistant students is imperative. OBJECTIVE: This study tested the hypothesis that students in long-term care departments who underwent immersive virtual reality (IVR) training would have significantly (1) higher levels of knowledge about the skills of nasogastric tube feeding, (2) higher learning motivations (i.e., intrinsic and extrinsic motivations, task values, and self-efficacy), (3) lower cognitive load, and (4) higher satisfaction than a control group. DESIGN: A randomized controlled trial with pretest and posttest design. SETTINGS AND PARTICIPANTS: We randomly assigned 107 students from the long-term care departments of two universities in central Taiwan to the IVR group (n = 54) or the control group (n = 53). METHODS: The IVR group learned the procedure of nasogastric tube feeding through IVR, whereas the control group watched a 15-min 2D video. The participants filled pretest and posttest questionnaires on nasogastric tube feeding knowledge. After the experiment was completed, the participants answered another questionnaire on their learning motivations, cognitive load, and learning satisfaction. RESULTS: The nasogastric tube feeding knowledge improved significantly in the IVR and control groups after the intervention, with no significant between-group differences. The IVR group scored significantly higher than the control group on extrinsic goals, task value, and satisfaction; nevertheless, they also experienced a significantly higher cognitive load. CONCLUSIONS: Both the IVR training and the traditional 2D video improved the learning outcomes of the nursing assistant students. The students were more satisfied with IVR than with the conventional learning model and indicated that IVR inspired their extrinsic learning motivations and perceived task value. However, IVR incurred a high cognitive load, which must be addressed in future course designs.


Assuntos
Estudantes de Enfermagem , Realidade Virtual , Humanos , Nutrição Enteral , Competência Clínica , Aprendizagem
4.
Artigo em Inglês | MEDLINE | ID: mdl-36293776

RESUMO

The utilization of preventive care services is limited. Previous studies based on communities have looked at many types of barriers to preventive care (i.e., why not do). This study aimed to gain an insight into the key factors and performance gaps (i.e., why do and how to do) of people who attended a regional teaching hospital to undergo health check-ups using a purposive sampling method to recruit people to complete a self-administered questionnaire. Paired sample t-tests and importance-performance gap and regression analyses were performed. The results indicated that the participants' wish to understand their health status, the quality of medical devices and the completeness of items, and process layout planning were the key factors that affect people's health check-up behavior. Promoting the effectiveness of hospital performance may improve the positive cycle of people's health check-up behavior from the community to the hospital. Continuing to promote the knowledge of preventive care services is necessary, and it is very important for people to have a good experience of undergoing health check-ups in the hospital. Important strategies for improving the utilization of preventive care services may include: meeting the person's personalization needs, improving the quality of medical devices and the completeness of items, and having appropriate process layout planning, a detailed interpretation of the results, and further follow-ups in the hospital.


Assuntos
Serviços Preventivos de Saúde , Humanos , Inquéritos e Questionários
5.
Res Vet Sci ; 151: 175-183, 2022 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-36041311

RESUMO

Suilysin (Sly) from Streptococcus suis has been shown to elicit strong immune responses and may act as a vaccine adjuvant. In the present study, we tested the adjuvant effect of Sly using an engineered Pasteurella multocida toxin, rPMT-NC, as the antigen. The antigen was also formulated with other conventional adjuvants (aluminum hydroxide, water-in-oil-in-water) for comparison. The efficacy of these vaccine formulations were evaluated in mice. The optimal dosage of purified rSly for enhancing immune responses in mice was first determined to be 40 µg/ml based on significantly (p < 0.05) increased serum antibody titers, expression of cytokines, including interleukin (IL)-4, IL-12, and interferon (IFN)-γ and the survival rate after challenge with P. multocida. Mice immunized with rPMT-NC + rSly had augmented antibody production and cellular immunity compare to those immunized with rPMT-NC plus other adjuvants. In addition, the survival rate of mice immunized with rPMT-NC + rSly was the highest (70% v.s. 30% of mice immunized with rPMT-NC alone) among all groups. In conclusion, rSly has the potential to be used as a biological adjuvant to enhance immune responses and protective efficacy of protein-based vaccines.


Assuntos
Pasteurella multocida , Streptococcus suis , Adjuvantes Imunológicos/farmacologia , Animais , Proteínas de Bactérias , Toxinas Bacterianas , Proteínas Hemolisinas , Camundongos , Água
6.
Risk Manag Healthc Policy ; 14: 4415-4424, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34737659

RESUMO

BACKGROUND: The health literacy of hospital patients has become a very important issue, especially in the face of emerging infectious diseases. The design of and measures used by hospitals, however, have not yet taken into account whether patients can develop their health literacy through the process of medical treatment. Hospitals should take on this role as part of health education programs. METHODS: A cross-sectional survey was conducted at pre-admission testing center patients waiting to be hospitalized in a regional teaching hospital. A purposive sampling method was used to recruit 406 patients via self-administered questionnaires. RESULTS: Among the 406 participants, 36.1% had adequate health literacy. There were significant differences in age, education attainment, and history of chronic diseases for health literacy. The ability to find and judge information on health was lower. Watching health-related TV programs was positively correlated with health literacy. Health literacy, health promotion literacy, and understanding information on health were positively correlated to self-care and management. 65.8% of patients did not understand the treatment for which they were being admitted. Health literacy, healthcare health literacy, the ability to judge health information were positively related to understanding the treatment. CONCLUSION: Health literacy is a critical facilitating factor in improving self-care and management and understanding treatment on admission. Health education programs cannot, however, be one-size-fits-all. To help patients change their behavior, the change must be made easy. To this end, health information in the form of entertainment programs and simplified materials may be useful and even necessary.

7.
Res Vet Sci ; 137: 138-143, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33975192

RESUMO

Pasteurella multocida (P. multocida) infects the swine respiratory tract and mainly causes atrophic rhinitis (AR). Recently, many commercially inactivated and subunit vaccines have been used as preventive strategies. However, the best antigenic protein portion has not been selected, and the aluminum gel was used as the adjuvant, which may not induce full protection. P. multocida toxin (PMT) is the major virulence factor responsible for AR. PMT is a monomeric 146 kDa protein (approximately 1285 amino acids) encoded by the tox A gene. In this study, we expressed different fragments of recombinant PMT proteins, combined them with a water-in-oil-in-water adjuvant, and evaluated mice's immune response. The results indicated that the rPMT-C-immunized group showed significantly higher levels (p < 0.05) of IgG, IgG2a antibody and interferon-γ, IL-12 cytokine expression than other groups. Furthermore, vaccination with rPMT-C recombinant protein can provide homologous and heterologous protection against P. multocida challenge. In conclusion, our approach may be feasible for developing an effective subunit vaccine against atrophic rhinitis with a cost-down simple ingredient.


Assuntos
Proteínas de Bactérias/imunologia , Toxinas Bacterianas/imunologia , Vacinas Bacterianas/imunologia , Infecções por Pasteurella/veterinária , Pasteurella multocida , Rinite Atrófica/prevenção & controle , Adjuvantes Imunológicos , Animais , Imunização , Camundongos , Camundongos Endogâmicos ICR , Infecções por Pasteurella/imunologia , Infecções por Pasteurella/prevenção & controle , Rinite Atrófica/imunologia , Vacinas Sintéticas/uso terapêutico
8.
Sci Rep ; 11(1): 1090, 2021 01 13.
Artigo em Inglês | MEDLINE | ID: mdl-33441668

RESUMO

Cardiolipin (CL), a crucial component in inner mitochondrial membranes, interacts with cytochrome c (cyt c) to form a peroxidase complex for the catalysis of CL oxidation. Such interaction is pivotal to the mitochondrial regulation of apoptosis and is affected by the redox state of cyt c. In the present study, the redox-dependent interaction of cyt c with CL was investigated through amide hydrogen/deuterium exchange coupled with mass spectrometry (HDXMS) and quartz crystal microbalance with dissipation monitoring (QCM-D). Ferrous cyt c exhibited a more compact conformation compared with its ferric form, which was supported by the lower number of deuterons accumulated and the greater amplitude reduction on dissipation. Upon association with CL, ferrous cyt c resulted in a moderate increase in deuteration, whereas the ferric form caused a drastic increase of deuteration, which indicated that CL-bound ferric cyt c formed an extended conformation. These results were consistent with those of the frequency (f) - dissipation (D) experiments, which revealed that ferric cyt c yielded greater values of |ΔD/Δf| within the first minute. Further fragmentation analysis based on HDXMS indicated that the effect of CL binding was considerably different on ferric and ferrous cyt c in the C-helix and the Loop 9-24. In ferric cyt c, CL binding affected Met80 and destabilized His18 interaction with heme, which was not observed with ferrous cyt c. An interaction model was proposed to explain the aforementioned results.


Assuntos
Cardiolipinas/metabolismo , Citocromos c/metabolismo , Animais , Citocromos c/química , Medição da Troca de Deutério , Cavalos , Espectrometria de Massas , Modelos Moleculares , Conformação Proteica , Técnicas de Microbalança de Cristal de Quartzo
9.
BMC Med Inform Decis Mak ; 20(1): 74, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32326949

RESUMO

BACKGROUND: The effects of patient sustained self-care behaviors on glycemic control are even greater than the effects of medical treatment, indicating the value of identifying the factors that influence self-care behaviors. To date, these factors have not been placed in a single model to clarify the critical path affecting self-care behaviors. The aims of this study were to explore the relationships of these factors and the differences in patient preference for medical decision-making. METHODS: A cross-sectional study was conducted among outpatients with type 2 diabetes at a regional teaching hospital. Purposive sampling was adopted to recruit 316 eligible patients via self-administered questionnaires. Partial least squares structural equation modeling was used for analysis. RESULTS: Significant direct pathways were identified from health literacy to self-efficacy, patient empowerment, and self-care behaviors; from self-efficacy to self-care behaviors; and from patient empowerment to self-care behaviors. Indirect pathways were from health literacy to self-care behaviors via self-efficacy or patient empowerment. The pathway from health literacy to self-efficacy was significantly stronger in those preferring shared decision-making than in those who preferred physician decision-making. CONCLUSIONS: Health literacy is a critical factor in improving self-care behaviors in patients with type 2 diabetes, and the effect of health literacy on self-efficacy was more significant in the shared decision-making than in the physician decision-making. Therefore, developing an effective health strategy to strengthen health literacy awareness and designing friendly, diverse health literacy materials, and application tools is the most important factor to facilitate self-care behaviors in this population.


Assuntos
Diabetes Mellitus Tipo 2 , Letramento em Saúde , Autocuidado , Idoso , Tomada de Decisão Clínica , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pacientes
10.
Patient Prefer Adherence ; 13: 871-879, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31213781

RESUMO

Background: Improving glycemic control requires that patients actively participate in decisions about how to best live with the disease and adapt to the realities of self-care. Limited health literacy (HL) is related to poorer health outcomes and may make it difficult for patients to participate in shared decision-making (SDM). As such, understanding the relationship between HL and SDM and its impact on diabetes control is an urgent issue. Methods: A cross-sectional survey was conducted among outpatients with type 2 diabetes in a regional teaching hospital. Purposive sampling was used to recruit eligible 372 patients via self-administered questionnaires. HbA1C values were obtained from each patient's laboratory assay. Results: Among the 372 participants, 50.4% of patients preferred physician decision-making, 39.3% preferred SDM, and 10.3% preferred patient decision-making. The physician explaining the illness in colloquial language, having adequate time for discussion, and encouragement from the healthcare provider were the major factors influencing patients' involvement in SDM. Interactive HL and critical HL had positive correlations with patients' perceived involvement in SDM. Educational attainment and HL were positively related. The HbA1C values for patient decision-making and physician decision-making were approximately 1.4 times and 1.24 times higher than those of SDM, respectively. Conclusion: SDM led to better glycemic control. HL increased patients' perceived involvement in SDM. Therefore, it is necessary to improve levels of HL based on the educational attainment of patients. Physicians explaining illness in colloquial language is the key factor in promoting patients' perceived involvement in SDM.

11.
J Microbiol Immunol Infect ; 52(1): 62-74, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29530709

RESUMO

BACKGROUND/PURPOSE: This study investigated the distribution and persistence of multidrug resistant organisms (MDROs) including methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and multidrug-resistant Acinetobacter baumannii (MDRAB) in six long-term care facilities (LTCFs). METHODS: We investigated the distribution of MDROs in residents of six LTCFs and their environments from January to December 2016 (intervention period). Active surveillance of colonization of MDROs was performed by culturing rectal and nasal swab samples from the residents every three months. Multilocus sequence typing (MLST) was conducted, and genes for panton-valentine leukocidin (PVL) from MRSA isolates were determined. RESULTS: A total of 521 samples were positive for MDROs, and MRSA was the most common organism (65.1%), followed by MDRAB (11.3%), carbapenem-resistant Klebsiella pneumoniae (11.1%), carbapenem-resistant Escherichia coli (4.6%), and carbapenem-resistant P. aeruginosa (2.1%, n = 11). By a linear regression model, positive MRSA isolates from the environment were found to be statistically significant and associated with the number of colonized LTCF residents (p = 0.01), while the timing of the surveillance culture was not (p = 0.227). The main MLST types associated with PVL-production were sequence type (ST) 59, (40.0%, 24/60), ST30 (21.4%, 3/14), ST8 (87.5%, 14/16), and ST45 (3.6%, 1/28). The susceptibility rates of tetracycline (96.7%), trimethoprim-sulfamethoxazole (96.7%), and ciprofloxacin (81.7%) were statistically significant and higher in MRSA ST59, compared to the rates in MRSA ST45 isolates. CONCLUSIONS: MRSA was the most commonly colonized MDRO, both in the LTCF residents and in the environment, followed by MDRAB and carbapenem-resistant K. pneumoniae.


Assuntos
Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana Múltipla , Microbiologia Ambiental , Assistência de Longa Duração/estatística & dados numéricos , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Acinetobacter baumannii/isolamento & purificação , Idoso , Idoso de 80 Anos ou mais , Antibacterianos/farmacologia , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/epidemiologia , Toxinas Bacterianas/genética , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Exotoxinas/genética , Feminino , Genótipo , Humanos , Leucocidinas/genética , Masculino , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Pessoa de Meia-Idade , Pseudomonas aeruginosa/isolamento & purificação , Taiwan/epidemiologia
13.
J Microbiol Immunol Infect ; 50(2): 133-144, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28373038

RESUMO

OBJECTIVES: This study investigated the prevalence of multidrug-resistant organisms (MDROs) in the residents and environments of long-term care facilities (LTCFs) in Taiwan. METHODS: We prospectively investigated the distribution of MDROs in residents of six LTCFs and their environments from January 2015 to December 2015 (intervention period). Active surveillance of colonization of MDROs was performed by culturing rectal and nasal swab samples every 3 months for the residents: 63, 79, and 73 in the first, second, and third surveillance investigations, respectively. If MDROs, including methicillin-resistant Staphylococcus aureus, carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa, and MDR Acinetobacter baumannii were identified, then swab specimens from environmental sources were also collected and cultured. During the study period, several infection control measures were also implemented. RESULTS: The overall infection density decreased significantly from 2.69 per 1000 patient-days in the preintervention (January 2014 to December 2014) to 2.39 per 1000 patient-days during the intervention period (p < 0.001). A total of 154 samples from residents and environmental sources were positive for MDROs. Methicillin-resistant S. aureus (n = 83, 53.9%) was the predominant organism, followed by carbapenem-resistant Enterobacteriaceae (n = 35, 22.7%), MDR A. baumannii (n = 30, 19.5%), and carbapenem-resistant P. aeruginosa (n = 6, 3.9%). The rates of detection of MDROs were 27.9% (60/215) in nasal swabs, 15.8% (34/215) in rectal swabs, and 11.1% (60/542) in the environmental sources. CONCLUSIONS: The distribution and persistence of MDROs varied among the different LTCFs and time periods.


Assuntos
Infecções Bacterianas/microbiologia , Microbiologia Ambiental , Assistência de Longa Duração/estatística & dados numéricos , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/patogenicidade , Idoso , Idoso de 80 Anos ou mais , Bactérias/isolamento & purificação , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/epidemiologia , Portador Sadio/epidemiologia , Portador Sadio/microbiologia , Farmacorresistência Bacteriana Múltipla , Enterobacteriaceae/efeitos dos fármacos , Enterobacteriaceae/patogenicidade , Feminino , Instalações de Saúde , Humanos , Controle de Infecções , Masculino , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Tipagem Molecular , Mucosa Nasal/microbiologia , Prevalência , Estudos Prospectivos , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Reto/microbiologia , Taiwan/epidemiologia
14.
Biochim Biophys Acta Proteins Proteom ; 1865(5): 539-546, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28242466

RESUMO

Cytochrome c (cyt c) is a mitochondrial protein responsible for transferring electrons between electron transport chain complexes III and IV. The release of cyt c from the mitochondria has been considered as a commitment step in intrinsic apoptosis. Transfer RNA (tRNA) has recently been found to interact with the released cyt c to prevent the formation of the apoptosome complex, thus preventing cell apoptosis. To understand the molecular basis of tRNA-cyt c interactions, we applied hydrogen/deuterium exchange mass spectrometry (HDXMS) to analyze the interactions between tRNA and cyt c. tRNAPhe binding to cyt c reduced the deuteration level of cyt c in all analyzed regions, indicating that tRNA binding blocks the solvent-accessible regions and results in the formation of a more compact conformation. Substitution of the tRNAPhe with the total tRNA from brewer's yeast in the HDXMS experiment significantly reduced deuteration in the N-terminus and the region 18-32 residue of cyt c, where all tRNAs are bound. To clarify the cause of binding, we used synthesized single-stranded oligonucleotides of 12-mer dA and dT to form complexes with cyt c. The exchange of the nucleotide bases between adenine and thymine did not affect the deuteration level of cyt c. However, the regions 1-10 and 65-82 showed minor decreases after unstructured dA or dT DNA binding. Collectively, these results reveal that cyt c maintains its globular structure to interact with tRNA. The region 18-32 selectively interacts with tRNA, and N-terminal 1-10 interacts with oligonucleotides electrostatically.


Assuntos
Citocromos c/química , Mitocôndrias/química , RNA de Transferência/química , Proteínas de Ligação a RNA/química , Apoptose/genética , Apoptossomas/química , Apoptossomas/genética , Citocromos c/genética , Citocromos c/metabolismo , Medição da Troca de Deutério , Complexo III da Cadeia de Transporte de Elétrons/química , Complexo III da Cadeia de Transporte de Elétrons/genética , Complexo IV da Cadeia de Transporte de Elétrons/química , Complexo IV da Cadeia de Transporte de Elétrons/genética , Espectrometria de Massas , Mitocôndrias/genética , Nucleotídeos/química , Oligonucleotídeos/química , Ligação Proteica , Conformação Proteica , RNA de Transferência/genética , RNA de Transferência/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Saccharomycetales/química , Saccharomycetales/genética
15.
Biochim Biophys Acta ; 1864(1): 42-51, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26542736

RESUMO

Cdc42 regulates pathways related to cell division. Dysregulation of Cdc42 can lead to cancer, cardiovascular diseases and neurodegenerative diseases. GTP induced activation mechanism plays an important role in the activity and biological functions of Cdc42. P-loop, Switch I and Switch II are critical regions modulating the enzymatic activity of Cdc42. We applied amide hydrogen/deuterium exchange coupled with liquid chromatography mass spectrometry (HDXMS) to investigate the dynamic changes of apo-Cdc42 after GDP, GTP and GMP-PCP binding. The natural substrate GTP induced significant decreases of deuteration in P-loop and Switch II, moderate changes of deuteration in Switch I and significant changes of deuteration in the α7 helix, a region far away from the active site. GTP binding induced similar effects on H/D exchange to its non-hydrolysable analog, GMP-PCP. HDXMS results indicate that GTP binding blocked the solvent accessibility in the active site leading to the decrease of H/D exchange rate surrounding the active site, and further triggered a conformational change resulting in the drastic decrease of H/D exchange rate at the remote α7 helix. Comparing the deuteration levels in three activation states of apo-Cdc42, Cdc42-GDP and Cdc42-GMP-PCP, the apo-Cdc42 has the most flexible structure, which can be stabilized by guanine nucleotide binding. The rates of H/D exchange of Cdc42-GDP are between the GMP-PCP-bound and the apo form, but more closely to the GMP-PCP-bound form. Our results show that the activation of Cdc42 is a process of conformational changes involved with P-loop, Switch II and α7 helix for structural stabilization.


Assuntos
Medição da Troca de Deutério/métodos , Nucleotídeos de Guanina/química , Conformação Proteica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Proteína cdc42 de Ligação ao GTP/química , Sequência de Aminoácidos , Nucleotídeos de Guanina/metabolismo , Guanosina Difosfato/química , Guanosina Difosfato/metabolismo , Guanosina Trifosfato/análogos & derivados , Guanosina Trifosfato/química , Guanosina Trifosfato/metabolismo , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Eletricidade Estática , Proteína cdc42 de Ligação ao GTP/genética , Proteína cdc42 de Ligação ao GTP/metabolismo
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