Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
PeerJ ; 12: e17290, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38650648

RESUMEN

Background: Gas expansion in body cavities due to pressure changes at high altitudes can cause barodontalgia. This condition may compromise flight safety. Aim: To investigate relationships among barodontalgia awareness, dental visit frequency, and barodontalgia prevalence in civilian and military pilots operating at high altitudes. Materials and Methods: Civilian pilots from Turkish Airlines and military pilots from the Turkish Air Force, flying between November 2022 and January 2023, participated in this study. A 20-question survey was administered to 750 pilots, covering topics such as barodontalgia awareness, dental visit frequency, breaks after dental treatments, in-flight pain, and pain type and severity. The voluntary surveys were distributed by email. Results: Of the 750 pilots, 526 completed the survey; 61% were aware of barodontalgia, and 81% of pilots who had experienced it reported pain at altitudes <2000 feet. The study revealed higher barodontalgia awareness among pilots who had experienced it, with the highest prevalence among jet pilots. Pilots with barodontalgia also showed a higher frequency of dental visits (p < 0.001). Additionally, this group reported more frequent interruption of flight due to dental treatment (IFDT), more problems experienced in flights after treatment (PFAT), and higher instances of bruxism or teeth clenching during flight, suggesting stress and anxiety (p < 0.05). Conclusions: Barodontalgia, a type of pain linked to stress, significantly impacts pilot performance, and can threaten flight safety, even at lower altitudes. Thus, there is a need to educate pilots about stress management, barodontalgia awareness, and the importance of regular dental check-ups.


Asunto(s)
Altitud , Personal Militar , Humanos , Turquía/epidemiología , Prevalencia , Masculino , Adulto , Personal Militar/psicología , Personal Militar/estadística & datos numéricos , Encuestas y Cuestionarios , Odontalgia/epidemiología , Odontalgia/psicología , Pilotos/psicología , Atención Odontológica/estadística & datos numéricos , Medicina Aeroespacial , Femenino , Persona de Mediana Edad
2.
BMC Oral Health ; 24(1): 502, 2024 Apr 28.
Artículo en Inglés | MEDLINE | ID: mdl-38679708

RESUMEN

OBJECTIVE: This cross-sectional online questionnaire-based study evaluated the knowledge, awareness, and behaviors of dentists and senior dental students regarding oral cancer (OC). MATERIALS AND METHODS: This study included 168 dentists and senior dental students who had completed all theoretical educations and clinical practices. An online survey was administered to all participants to assess their awareness of the risk factors for OC, clinical knowledge, and behaviors. The participants' demographic characteristics and knowledge of OC were analyzed. RESULTS: Of the participants, 48.8% were female and 51.2% were male. Their mean age was 27.04 ± 5.56 years (range: 21-51). In addition, 59.5% were dentists, and 40.5% were senior dental students. The dentists' mean time since graduation was 6.38 ± 5.64 years (range: 1-27). Routine oral mucosa examination for OC was significantly more frequent among the dentists than the senior dental students (p < 0.05). Among all participants, 33% of dentists and 51.5% of senior dental students had poor knowledge of OC-related or possibly predisposing factors. Routine evaluation of OC-related and predisposing risk factors, including human papillomavirus infection, smoking, alcohol use, trauma-related non-healing oral lesions caused by long-term incompatible prostheses, and poor oral hygiene, was significantly more frequent among the dentists than the senior dental students (p < 0.05). CONCLUSION: Educating dental students about a more comprehensive oral examination and early diagnosis of OC would help overcome the current lack of adequate knowledge and attitudes in OC prevention and early detection. A core curriculum compatible with the global standards on OC should be provided to dental students.


Asunto(s)
Odontólogos , Conocimientos, Actitudes y Práctica en Salud , Neoplasias de la Boca , Estudiantes de Odontología , Humanos , Estudiantes de Odontología/psicología , Femenino , Estudios Transversales , Masculino , Adulto , Odontólogos/psicología , Adulto Joven , Persona de Mediana Edad , Encuestas y Cuestionarios , Factores de Riesgo , Actitud del Personal de Salud
3.
Int J Med Inform ; 185: 105409, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38471408

RESUMEN

AIM: To evaluate YouTube videos on vital pulp capping (VPC) for content, quality, source, usefulness, and reliability. MATERIALS AND METHODS: This study assessed 249 English-language videos on vital pulp therapy using the Total Content Score (TCS), Video Information and Quality Index (VIQI), Global Quality Scale (GQS), Journal of the American Medical Association (JAMA) score and modified DISCERN score. Videos were categorized based on communication quality, duration, likes and dislikes, views, source, and video type. Of the videos analyzed, 22.1% met the inclusion criteria. Data were analyzed using Shapiro-Wilk, Kruskal-Wallis, and post hoc Bonferroni tests. Sperman's correlation, Kendal tau tests for correlations, and Fisher's exact test were used to assess associations between categorical variables. RESULTS: The study identified significant correlations between various parameters. A higher TCS was correlated with increased VIQI (p = 0.005) and GQS scores (r = 0.685, p < 0.05). A moderate positive correlation was found between GQS scores and TCSs (r = 0.577, p < 0.05). VIQI scores were significantly and positively correlated with TCS (r = 0.573, p < 0.05) and comment count (r = 0.306, p < 0.05). JAMA scores were positively correlated with upload time (r = 0.304, p < 0.05), comment count (r = 0.337, p < 0.05), and likes (r = 0.301, p = 0.05). CONCLUSIONS: YouTube videos provided low-to-average quality VPC information and tended to be inaccurate. Therefore, public videos may be incorrect, incomplete, and low-quality. Clinicians and patients should seek reliable information from specialists.


Asunto(s)
Recubrimiento de la Pulpa Dental , Medios de Comunicación Sociales , Estados Unidos , Humanos , Reproducibilidad de los Resultados , Aprendizaje , Comunicación , Atención Odontológica
4.
Odontology ; 2024 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-38252232

RESUMEN

Bacterial products, host immune cells and cytokines have been reported to play an important role in the pathogenesis of apical periodontitis (AP). This study aimed to determine the main bacterial species in the microbiota as gram positive and negative and to compare the relationship between matrix metalloproteinase (MMP)-9 and tumor necrosis factor (TNF)-α with controlled patient groups. 60 patients with AP and extraction indication were included in the study. 30 systemically healthy volunteers without AP were selected as the control group. After access cavity preparation, an initial microbiologic sample (S1) was taken from the root canal. After atraumatic extraction of the tooth, a second microbial sample (S2) was taken from the extraradicular region. After bacterial DNA extraction, 16S rRNA gene primer was designed for sequence analysis. Bacterial community profiling was made by Sanger sequencing of the PCR products. In addition, serum MMP-9 and TNF-α levels were measured from all patients. TNF-α levels of the AP group were higher than the control group, while MMP-9 levels were found to be lower (p = 0.0264 and p = 0.0146, respectively). There was no difference in the main bacterial species isolated from the samples taken from the intracanal and extraradicular region of the tooth with AP (p = 0.714). The main bacterial species in the intracanal region of the tooth with AP are similar to the main bacterial species in the extraradicular region. The pathophysiology of the tooth with AP is associated with low MMP-9 and high TNF-α, independent of the bacterial species in the intracanal and extraradicular regions.

5.
Odontology ; 111(3): 708-718, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36414882

RESUMEN

To investigate the relationship between apical periodontitis [AP] severity and inflammatory markers [interleukin (IL)-12, tumor necrosis factor-alpha (TNF-α), and Mid-Regional Pro Adrenomedullin (MR-proADM)] in patients with AP. A total of 162 subjects were divided into three categories: AP group (n = 80), periodontitis (P) group (n = 42), healthy control group (n = 40). The scoring of disease severity in 80 AP patients without any periodontal disease, using dental radiographs, was based on "The Abscess Score" (AS), as those having at least 1 tooth with AP and severity of PAI 3-4 were classified as AS 1 (mild); those with only1 tooth and severity of PAI 5 as AS 2 (moderate) and those having > 2 tooth with severity of PAI 5 as AS 3 (severe). Blood samples were collected from all of the patients. Enzyme-linked immunosorbent assay was used to evaluate the samples. The MR-pro ADM levels of both the AP and P groups were considerably higher than the control group (p < 0.01). The IL-12 levels of the AP group were higher than the P and control groups (p < 0.05). TNF-α levels of the P group were significantly higher than both the AP and control groups (p < 0.01). MR-pro ADM levels of both the AP and Periodontitis groups were higher than the control group. TNF-α was a biomarker of periodontitis, while IL-12 was a biomarker of apical periodontitis.


Asunto(s)
Periodontitis Periapical , Periodontitis , Humanos , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba , Adrenomedulina , Biomarcadores , Interleucina-12
6.
BMC Oral Health ; 22(1): 590, 2022 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-36494809

RESUMEN

The purpose of this study is to investigate the effects of different root canal irrigation protocols applied to the dentin and artificial aging procedures on the micro pushout bond strength (mPBS) between dentin and hybrid ceramic posts. Seventy-five single-rooted mandibular premolar teeth were divided into 5 groups (Gr1-5). 50 of the teeth were used for the mPBS tests (n = 10), whereas 25 were used for the smear layer examinations (n = 5). Post space were prepared and irrigated with different irrigation-protocols in each group. (Gr1:[SS], Gr2:[NaOCl] + SS, Gr3:[EDTA] + NaOCl + SS, Gr4:[MA] + NaOCl + SS, Gr5:[Ch] + NaOCl + SS). Post and core pattern were fabricated with pattern resin and a fiber post, after scanning, the posts were milled with Vita Enamic resin ceramic block, and cemented. After 7 days the roots were sliced at thicknesses of 1 mm; half of them were subjected to mPBS test, while the other half were tested after undergoing mechanical cycling for artificial aging. For data analysis, the Shapiro-Wilk test was utilized to test normal distributions, 3-way analysis of variance was used to compare mPBS, and Tukey's HSD test was conducted for multiple comparisons. SEM analysis was performed for examination of failure modes and smear layer removal. Different root canal irrigation protocols affected mPBS significantly. While Gr4 had the highest mPBS, Gr1 had the lowest. Regarding to different zones, the highest mPBS was in coronal zone, and the lowest one was in the apical zone. The aging procedure also led to a statistically-significant decrease in mPBS. Most frequent failure modes were cohesive failure in dentin and mixed failure. Irrigation with 7%MA (Gr4) showed better performance than 17% EDTA (Gr3) in smear layer removal, especially at the apical zone of the tooth. This is critical for the success of root canal treatment and increased the mPBS to a higher extent in all zones of the tooth.


Asunto(s)
Recubrimiento Dental Adhesivo , Capa de Barro Dentinario , Humanos , Irrigantes del Conducto Radicular/uso terapéutico , Irrigantes del Conducto Radicular/química , Cavidad Pulpar , Dentina , Recubrimiento Dental Adhesivo/métodos , Hipoclorito de Sodio/uso terapéutico , Hipoclorito de Sodio/química , Ácido Edético/análisis , Ácido Edético/química , Ácido Edético/farmacología , Diente Premolar , Preparación del Conducto Radicular/métodos , Ensayo de Materiales
7.
Med Sci Monit ; 28: e937339, 2022 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-36016478

RESUMEN

BACKGROUND One of the aims of endodontic treatment is to control preoperative and postoperative pain. The present study evaluated the effects of local and systemic ibuprofen on postoperative pain. It aimed to determine the most effective method for relieving postoperative pain due to chemomechanical preparation. MATERIAL AND METHODS Ninety patients with symptomatic apical periodontitis were randomly assigned to local ibuprofen, systemic ibuprofen, and control groups (n=30 each). Chemomechanical preparations were performed using a ProTaper Universal Ni-Ti rotary file under 2.5% sodium hypochlorite and 17% ethylenediaminetetraacetic acid irrigation. After the root canals were dried with sterile paper points, while Odontocide paste was applied into the root canals of the patients in the local ibuprofen group, calcium hydroxide paste was applied into the root canals of the patients in the systemic ibuprofen and control groups. Following completion of the endodontic treatment procedure, 200 mg ibuprofen was prescribed to patients in the systemic ibuprofen group. Friedman and Wilcoxon tests were used for statistical analysis. RESULTS Posttreatment pain scores were recorded at 6, 12, 24, and 48 h using a visual analogue scale. Although there were no significant differences between the local ibuprofen group (Odontocide) and the control group (Ultracal) (P>0.05), pain scores in the systemic group (Ultracal+200 mg ibuprofen) were significantly lower than those in the other 2 groups (P<0.05). CONCLUSIONS These results indicate that systemic administration of ibuprofen is effective for postoperative pain relief.


Asunto(s)
Ibuprofeno , Periodontitis Periapical , Humanos , Ibuprofeno/uso terapéutico , Dolor Postoperatorio/tratamiento farmacológico , Periodontitis Periapical/tratamiento farmacológico , Periodontitis Periapical/cirugía , Irrigantes del Conducto Radicular/uso terapéutico , Preparación del Conducto Radicular/métodos
8.
Biomolecules ; 10(1)2020 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-31936876

RESUMEN

Lipoproteins are supramolecular assemblies of proteins and lipids with dynamic characteristics critically linked to their biological functions as plasma lipid transporters and lipid exchangers. Among them, spherical high-density lipoproteins are the most abundant forms of high-density lipoprotein (HDL) in human plasma, active participants in reverse cholesterol transport, and associated with reduced development of atherosclerosis. Here, we employed elastic incoherent neutron scattering (EINS) and hydrogen-deuterium exchange mass spectrometry (HDX-MS) to determine the average particle dynamics and protein backbone local mobility of physiologically competent discoidal and spherical HDL particles reconstituted with human apolipoprotein A-I (apoA-I). Our EINS measurements indicated that discoidal HDL was more dynamic than spherical HDL at ambient temperatures, in agreement with their lipid-protein composition. Combining small-angle neutron scattering (SANS) with contrast variation and MS cross-linking, we showed earlier that the most likely organization of the three apolipoprotein A-I (apoA-I) chains in spherical HDL is a combination of a hairpin monomer and a helical antiparallel dimer. Here, we corroborated those findings with kinetic studies, employing hydrogen-deuterium exchange mass spectrometry (HDX-MS). Many overlapping apoA-I digested peptides exhibited bimodal HDX kinetics behavior, suggesting that apoA-I regions with the same amino acid composition located on different apoA-I chains had different conformations and/or interaction environments.


Asunto(s)
Apolipoproteína A-I/química , Lipoproteínas HDL/química , Medición de Intercambio de Deuterio , Humanos , Cinética , Espectrometría de Masas , Modelos Moleculares , Difracción de Neutrones , Conformación Proteica , Multimerización de Proteína , Dispersión del Ángulo Pequeño
9.
J Biol Chem ; 293(23): 8843-8860, 2018 06 08.
Artículo en Inglés | MEDLINE | ID: mdl-29643180

RESUMEN

Aminoacyl-tRNA synthetases are ubiquitous, evolutionarily conserved enzymes catalyzing the conjugation of amino acids onto cognate tRNAs. During eukaryotic evolution, tRNA synthetases have been the targets of persistent structural modifications. These modifications can be additive, as in the evolutionary acquisition of noncatalytic domains, or subtractive, as in the generation of truncated variants through regulated mechanisms such as proteolytic processing, alternative splicing, or coding region polyadenylation. A unique variant is the human glutamyl-prolyl-tRNA synthetase (EPRS) consisting of two fused synthetases joined by a linker containing three copies of the WHEP domain (termed by its presence in tryptophanyl-, histidyl-, and glutamyl-prolyl-tRNA synthetases). Here, we identify site-selective proteolysis as a mechanism that severs the linkage between the EPRS synthetases in vitro and in vivo Caspase action targeted Asp-929 in the third WHEP domain, thereby separating the two synthetases. Using a neoepitope antibody directed against the newly exposed C terminus, we demonstrate EPRS cleavage at Asp-929 in vitro and in vivo Biochemical and biophysical characterizations of the N-terminally generated EPRS proteoform containing the glutamyl-tRNA synthetase and most of the linker, including two WHEP domains, combined with structural analysis by small-angle neutron scattering, revealed a role for the WHEP domains in modulating conformations of the catalytic core and GSH-S-transferase-C-terminal-like (GST-C) domain. WHEP-driven conformational rearrangement altered GST-C domain interactions and conferred distinct oligomeric states in solution. Collectively, our results reveal long-range conformational changes imposed by the WHEP domains and illustrate how noncatalytic domains can modulate the global structure of tRNA synthetases in complex eukaryotic systems.


Asunto(s)
Aminoacil-ARNt Sintetasas/metabolismo , Caspasas/metabolismo , Aminoacil-ARNt Sintetasas/química , Dominio Catalítico , Glutamato-ARNt Ligasa/química , Glutamato-ARNt Ligasa/metabolismo , Células HEK293 , Humanos , Modelos Moleculares , Conformación Proteica , Dominios Proteicos , Proteolisis
10.
J Proteome Res ; 17(3): 1183-1193, 2018 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-29411613

RESUMEN

Isolation of high density lipoproteins (HDL) for structural and functional studies typically relies on ultracentrifugation techniques, which are time-consuming and difficult to scale. With emerging interest in the clinical relevance of HDL structure and function to cardiovascular disease, a significant gap exists between current and desirable sample preparation throughput. To enable proteomic studies of HDL with large clinical cohorts, we have developed an affinity enrichment approach that relies on the association of histidine-tagged, lipid free ApoA-I with HDL followed by standard metal chelate chromatography. Characterization of the resulting affinity-enriched ApoA-I associated lipoprotein (AALP) pool using biochemical, electrophoretic, and proteomic analysis demonstrates that the isolated material is closely related in structural features, lipid content, protein complement, and relative protein distribution to HDL isolated by ultracentrifugation using sequential density adjustment. The simplicity of the method provides avenues for high-throughput analysis of HDL associated proteins.


Asunto(s)
Apolipoproteína A-I/química , Cromatografía de Afinidad/métodos , Lipoproteínas HDL/aislamiento & purificación , Proteoma/aislamiento & purificación , Proteómica/métodos , Apolipoproteína A-I/metabolismo , Electroforesis en Gel de Poliacrilamida , Ontología de Genes , Ensayos Analíticos de Alto Rendimiento , Humanos , Lipoproteínas HDL/química , Lipoproteínas HDL/metabolismo , Anotación de Secuencia Molecular , Proteoma/química , Proteoma/metabolismo
11.
Clin Chem ; 64(4): 697-704, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29321128

RESUMEN

BACKGROUND: Lipoprotein-associated phospholipase A2 (Lp-PLA2), an enzyme associated with inflammation, is used as a biomarker for cardiovascular disease risk. Both the concentration and activity of Lp-PLA2 have been shown to be clinically relevant. However, there is a discordance between the serum concentration of Lp-PLA2 measured by the standard ELISA-based immunoassays and the activity of this enzyme, leading to substantial discordance in risk categorization depending on assay format. METHODS: We developed 2 LC-MS/MS-based assays to quantify serum Lp-PLA2 activity (multiple reaction monitoring detection of product) and concentration [stable isotope standards and capture by antipeptide antibody (SISCAPA) immunoaffinity], and we investigated their correlation to commercially offered colorimetric activity and immunometric concentrations assays. Associations between Lp-PLA2 and lipoproteins and the effect of selected detergents in liberating Lp-PLA2 were evaluated by use of immunoprecipitation and Western blot analyses. RESULTS: Serum Lp-PLA2 concentrations measured by quantitative SISCAPA-mass spectrometry were substantially higher than concentrations typically measured by immunoassay and showed an improved agreement with Lp-PLA2 activity. With detergents, liberation of Lp-PLA2 from lipoprotein complexes dramatically increased the amount of protein detected by immunoassay and improved the agreement with activity measurements. CONCLUSIONS: Quantitative analysis of Lp-PLA2 concentration and activity by LC-MS/MS assays provided key insight into resolving the well-documented discordance between Lp-PLA2 concentration (determined by immunoassay) and activity. Quantitative detection of Lp-PLA2 by immunoassay appears to be strongly inhibited by interaction of Lp-PLA2 with lipoprotein. Together, the results illustrate the advantages of quantitative LC-MS/MS for measurement of Lp-PLA2 concentration (by SISCAPA) and activity (by direct product detection).


Asunto(s)
1-Alquil-2-acetilglicerofosfocolina Esterasa/sangre , Cromatografía Liquida/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Espectrometría de Masas en Tándem/métodos , Western Blotting , Colesterol/sangre , Detergentes/química , Humanos , Inmunoprecipitación , Lipoproteínas/sangre
12.
J Biol Chem ; 289(15): 10276-10292, 2014 Apr 11.
Artículo en Inglés | MEDLINE | ID: mdl-24558038

RESUMEN

We reported previously that apolipoprotein A-I (apoA-I) is oxidatively modified in the artery wall at tyrosine 166 (Tyr(166)), serving as a preferred site for post-translational modification through nitration. Recent studies, however, question the extent and functional importance of apoA-I Tyr(166) nitration based upon studies of HDL-like particles recovered from atherosclerotic lesions. We developed a monoclonal antibody (mAb 4G11.2) that recognizes, in both free and HDL-bound forms, apoA-I harboring a 3-nitrotyrosine at position 166 apoA-I (NO2-Tyr(166)-apoA-I) to investigate the presence, distribution, and function of this modified apoA-I form in atherosclerotic and normal artery wall. We also developed recombinant apoA-I with site-specific 3-nitrotyrosine incorporation only at position 166 using an evolved orthogonal nitro-Tyr-aminoacyl-tRNA synthetase/tRNACUA pair for functional studies. Studies with mAb 4G11.2 showed that NO2-Tyr(166)-apoA-I was easily detected in atherosclerotic human coronary arteries and accounted for ∼ 8% of total apoA-I within the artery wall but was nearly undetectable (>100-fold less) in normal coronary arteries. Buoyant density ultracentrifugation analyses showed that NO2-Tyr(166)-apoA-I existed as a lipid-poor lipoprotein with <3% recovered within the HDL-like fraction (d = 1.063-1.21). NO2-Tyr(166)-apoA-I in plasma showed a similar distribution. Recovery of NO2-Tyr(166)-apoA-I using immobilized mAb 4G11.2 showed an apoA-I form with 88.1 ± 8.5% reduction in lecithin-cholesterol acyltransferase activity, a finding corroborated using a recombinant apoA-I specifically designed to include the unnatural amino acid exclusively at position 166. Thus, site-specific nitration of apoA-I at Tyr(166) is an abundant modification within the artery wall that results in selective functional impairments. Plasma levels of this modified apoA-I form may provide insights into a pathophysiological process within the diseased artery wall.


Asunto(s)
Apolipoproteína A-I/metabolismo , Placa Aterosclerótica/metabolismo , Tirosina/metabolismo , Animales , Anticuerpos Monoclonales/química , Aorta/metabolismo , Vasos Coronarios/patología , Escherichia coli/metabolismo , Humanos , Masculino , Ratones , Ratones Endogámicos BALB C , Peroxidasas/metabolismo , Procesamiento Proteico-Postraduccional , Especies de Nitrógeno Reactivo , Proteínas Recombinantes/metabolismo , Tirosina/análogos & derivados , Ultracentrifugación
13.
J Lipid Res ; 54(4): 966-83, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23349207

RESUMEN

Small-angle neutron scattering (SANS) with contrast variation was used to obtain the low-resolution structure of nascent HDL (nHDL) reconstituted with dimyristoyl phosphatidylcholine (DMPC) in the absence and presence of cholesterol, [apoA1:DMPC (1:80, mol:mol) and apoA1:DMPC:cholesterol (1:86:9, mol:mol:mol)]. The overall shape of both particles is discoidal with the low-resolution structure of apoA1 visualized as an open, contorted, and out of plane conformation with three arms in nascent HDL/dimyristoyl phosphatidylcholine without cholesterol (nHDL(DMPC)) and two arms in nascent HDL/dimyristoyl phosphatidylcholine with cholesterol (nHDL(DMPC+Chol)). The low-resolution shape of the lipid phase in both nHDL(DMPC) and nHDL(DMPC+Chol) were oblate ellipsoids, and fit well within their respective protein shapes. Modeling studies indicate that apoA1 is folded onto itself in nHDL(DMPC), making a large hairpin, which was also confirmed independently by both cross-linking mass spectrometry and hydrogen-deuterium exchange (HDX) mass spectrometry analyses. In nHDL(DMPC+Chol), the lipid was expanded and no hairpin was visible. Importantly, despite the overall discoidal shape of the whole particle in both nHDL(DMPC) and nHDL(DMPC+Chol), an open conformation (i.e., not a closed belt) of apoA1 is observed. Collectively, these data show that full length apoA1 retains an open architecture that is dictated by its lipid cargo. The lipid is likely predominantly organized as a bilayer with a micelle domain between the open apoA1 arms. The apoA1 configuration observed suggests a mechanism for accommodating changing lipid cargo by quantized expansion of hairpin structures.


Asunto(s)
Colesterol/química , Dimiristoilfosfatidilcolina/química , Lipoproteínas de Alta Densidad Pre-beta/química , Apolipoproteína A-I/química , Humanos , Espectrometría de Masas , Dispersión del Ángulo Pequeño
14.
Acta Crystallogr D Biol Crystallogr ; 68(Pt 6): 686-94, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22683791

RESUMEN

Parasitic organisms are constantly challenged by the defence mechanisms of their respective hosts, which often depend on serine protease activities. Consequently, protease inhibitors such as those belonging to the serpin superfamily have emerged as protective elements that support the survival of the parasites. This report describes the crystal structure of ShSPI, a serpin from the trematode Schistosoma haematobium. The protein is exposed on the surface of invading cercaria as well as of adult worms, suggesting its involvement in the parasite-host interaction. While generally conforming to the well established serpin fold, the structure reveals several distinctive features, mostly concerning the helical subdomain of the protein. It is proposed that these peculiarities are related to the unique biological properties of a small serpin subfamily which is conserved among pathogenic schistosomes.


Asunto(s)
Schistosoma haematobium/química , Serpinas/química , Secuencia de Aminoácidos , Animales , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Alineación de Secuencia , Homología Estructural de Proteína
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...