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1.
Molecules ; 29(5)2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38474484

RESUMO

The determination and evaluation of 16 polycyclic aromatic hydrocarbons (PAHs) in seven Chinese herbal medicines (CHMs) were conducted through a rapid and straightforward extraction and purification method, coupled with GC-MS. A sample-based solid-phase extraction (SPE) pretreatment technique, incorporating isotopic internal standards, was employed for detecting various medicinal parts of CHMs. The assay exhibited linearity within the range of 5 to 500 ng/mL, with linear coefficients (R2) for PAHs exceeding 0.999. The recoveries of spiked standards ranged from 63.37% to 133.12%, with relative standard deviations (RSDs) ranging from 0.75% to 14.54%. The total PAH content varied from 176.906 to 1414.087 µg/kg. Among the 16 PAHs, phenanthrene (Phe) was consistently detected at the highest levels (47.045-168.640 µg/kg). Characteristic ratio analysis indicated that oil, coal, and biomass combustion were the primary sources of PAHs in CHMs. The health risk associated with CHMs was assessed using the lifetime carcinogenic risk approach, revealing potential health risks from the consumption of honeysuckle, while the health risks of consuming Lycium chinense berries were deemed negligible. For the other five CHMs (glycyrrhizae, Coix lacryma, ginseng, lotus seed, seed of Sterculia lychnophora), the health risk from consumption fell within acceptable ranges. Furthermore, sensitivity analyses utilizing Monte Carlo exposure assessment methods identified PAH levels in CHMs as health risk sensitizers. It is crucial to recognize that the consumption of herbal medicines is not a continuous process but entails potential health risks. Hence, the monitoring and risk assessment of PAH residues in CHMs demand careful attention.


Assuntos
Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos , Monitoramento Ambiental/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Cromatografia Gasosa-Espectrometria de Massas , Medição de Risco , Extratos Vegetais/análise , China
2.
Pestic Biochem Physiol ; 194: 105522, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37532306

RESUMO

Insects are frequently exposed to a range of insecticides that can alter the structure of the commensal microbiome. However, the effects of exposure to non-target pesticides (including non-target insecticides and fungicides) on insect pest microbiomes are still unclear. In the present study, we exposed Nilaparvata lugens to three target insecticides (nitenpyram, pymetrozine, and avermectin), a non-target insecticide (chlorantraniliprole), and two fungicides (propiconazole and tebuconazole), and observed changes in the microbiome's structure and function. Our results showed that both non-target insecticide and fungicides can disrupt the microbiome's structure. Specifically, symbiotic bacteria of N. lugens were more sensitive to non-target insecticide compared to target insecticide, while the symbiotic fungi were more sensitive to fungicides. We also found that the microbiome in the field strain was more stable under pesticides exposure than the laboratory strain (a susceptible strain), and core microbial species g_Pseudomonas, s_Acinetobacter soli, g_Lactobacillus, s_Metarhizium minus, and s_Penicillium citrinum were significantly affected by specifically pesticides. Furthermore, the functions of symbiotic bacteria in nutrient synthesis were predicted to be significantly reduced by non-target insecticide. Our findings contribute to a better understanding of the impact of non-target pesticides on insect microbial communities and highlight the need for scientific and rational use of pesticides.


Assuntos
Fungicidas Industriais , Hemípteros , Inseticidas , Microbiota , Praguicidas , Animais , Inseticidas/toxicidade , Praguicidas/farmacologia , Fungicidas Industriais/farmacologia , Bactérias , Resistência a Inseticidas
3.
Langmuir ; 39(17): 6249-6257, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37073894

RESUMO

Developing advanced oil-water separation technology is significant for environmental conservation. According to the synergetic effects of the size-sieving mechanism, superwetting materials with small pore sizes have been designed to realize high-efficiency separation for oil-water emulsions. However, the separation flux limited by the pore size and the weakness of the superwetting material impede its practical application severely. Herein, we construct a robust Janus superwetting textile with large pore sizes for oil-in-water emulsion separation. The pristine textile is coated by the as-prepared CuO nanoparticles as the bottom layer with superhydrophilicity and then grafted by 1-octadecanethiol as the top layer with superhydrophobicity to construct the Janus textile. When used as a filter, the superhydrophobic layer acts as the nucleation site to coalesce the small oil droplets facilely. Then, the coalesced oil fills the pores of the superhydrophobic layer and selectively permeates it but is blocked by the superhydrophilic layer with large pore sizes. Utilizing the unique separation mechanism, the Janus textile realizes efficient and rapid separation. Even after multicycle separation, hot liquid immersion for 24 h, tribological test for 60 min, and sandpaper abrasion for 500 cycles, the Janus textile still retains the superwettability and excellent separation performance, manifesting outstanding stability to resist severe damage. This separation strategy provides a novel guideline for high-efficiency and high-flux emulsion separation and practical application.

4.
ACS Appl Mater Interfaces ; 15(10): 13700-13710, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36862602

RESUMO

To alleviate the economic and environmental damage caused by industrial discharges of oily wastewater, materials applied for efficient oil/water separation are receiving significant attention from researchers and engineers. Among others, switchable wettable materials for bidirectional oil/water separation show great potential for practical applications. Inspired by mussels, we utilized a simple immersion method to construct a polydopamine (PDA) coating on a peony-like copper phosphate surface. Then, TiO2 was deposited on the PDA coating surface to build a micro-nano hierarchical structure, which was modified with octadecanethiol (ODT) to obtain a switchable wettable peony-like superhydrophobic surface. The water contact angle of the obtained superhydrophobic surface reached 153.5°, and the separation efficiency was as high as 99.84% with a flux greater than 15,100 L/(m2·h) after 10 separation cycles for a variety of heavy oil/water mixtures. Notably, the modified membranes have a unique photoresponsiveness, transforming to superhydrophilic upon ultraviolet irradiation, achieving separation efficiencies of up to 99.83% and separation fluxes greater than 32,200 L/(m2·h) after 10 separation cycles for a variety of light oil/water mixtures. More importantly, this switch behavior is reversible, and the high hydrophobicity can be restored after heating to achieve efficient separation of heavy oil/water mixtures. In addition, the prepared membranes can maintain high hydrophobicity under acid-base conditions and after 30 sandpaper abrasion cycles, and damaged membranes can be restored to superhydrophobicity after a brief modification in the ODT solution. This simple-to-prepare, easy-to-repair, robust membrane with switchable wettability shows great potential in the field of oil/water separation.

5.
Langmuir ; 38(40): 12217-12228, 2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36169614

RESUMO

Polydopamine as a multifunctional biomimetic polymer with nonselective strong adhesion properties has become a hot research topic in recent years. However, there are a few reports on the durable and effective emulsion separation of polydopamine composites from other materials. Therefore, it is necessary to construct durable polydopamine composites to achieve selective adsorption of materials. In this work, polypyrrole (PPy)-PDA was obtained on sponges by an in situ polymerization reaction, followed by the attachment of SiO2 nanoparticles to the surface by polydimethylsiloxane to achieve superhydrophobicity. As a result, previously unreported selective superhydrophobic adsorbents for PPy-PDA coatings were obtained. The prepared sponges have an excellent adsorption capacity for oils and organic solvents. Not only can the sponges absorb 19-39 g of organic solvents per gram but they can also absorb oil from oil-in-water emulsions. The chemical oxygen demand value of the emulsion can be reduced to 219 mg/L after separation. More importantly, the performance remains good in the cycle test, and due to the construction of a durable superhydrophobic sponge, it can still maintain its relatively good performance in artificial seawater, acid-base environments, and can achieve relatively stable emulsion separation. At the same time, the potential of the polymer material composited with PDA in lasting and stable emulsion separation was also verified.

6.
Nat Prod Res ; 36(8): 1996-2001, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33118393

RESUMO

Three undescribed prenylated benzoic acid derivatives berberisides A-C (1-3) and a new clerodane glycoside berberiside D (4) were isolated from Berberis tsarica Aherndt. Their structures were elucidated on the basis of extensive NMR and HR-ESI-MS analysis. The in vitro cytotoxic activities of all isolates were studied against lung carcinoma A549, hepatocellular carcinoma HepG2 and breast carcinoma MDA-MB-231 cell lines. Among them, compounds 1 and 4 exhibited anti-proliferative effects against three tumor cell lines with IC50 ranging from 28.97 ± 2.18 to 35.83 ± 0.72 µM.


Assuntos
Berberis , Diterpenos Clerodânicos , Ácido Benzoico , Linhagem Celular Tumoral , Diterpenos Clerodânicos/farmacologia , Glicosídeos/farmacologia , Humanos , Estrutura Molecular
7.
Nat Prod Res ; 36(13): 3331-3336, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33289429

RESUMO

Zanthoxylum armatum, its peels possessed better special flavour, as well as various bioactivities, such as anti-inflammatory, anti-microbial and anti-tumour. In our chemical investigation on the peels of Z. armatum, two new lignans (1 and 2) and three known lignans (3-5) were isolated by silica gel column chromatography, ODS column and preparative HPLC and their structures were established as zanthlignans A and B (1-2), (-)-asarinin (3), phylligenin (4) and planispine A (5) through various spectroscopic techniques including UV, IR, HR-ESI-MS, NMR and CD methods.


Assuntos
Lignanas , Zanthoxylum , Anti-Inflamatórios , Cromatografia Líquida de Alta Pressão/métodos , Lignanas/química , Extratos Vegetais/química , Zanthoxylum/química
8.
Fitoterapia ; 151: 104886, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33757847

RESUMO

Two undescribed sesamin-type sesquilignans ptehoosines A (1) and B (2), together with 4 known lignans (3-6), were isolated from Pterocephalus hookeri (C.B. Clarke) Höeck which was widely used as traditional Tibetan medicine for treatment of rheumatoid arthritis. Their structures were determined by HR-ESI-MS, NMR analysis and CD experiment. The in vitro antiangiogenic effect of all isolated compounds against human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8 assay. Among them, compound 1 exhibited significant proliferative inhibition on HUVECs with IC50 value of 32.82 ± 0.99 µM. Further in vitro study indicated 1 could arrest cell cycle at G0/G1 phase and reduce the migration of HUVECs. In vivo experiment exhibited 1 could inhibit tail vessels plexus in zebrafish. The above finding suggested that 1 was a promising lead compound against RA by inhibiting of angiogenesis.


Assuntos
Inibidores da Angiogênese/farmacologia , Caprifoliaceae/química , Dioxóis/farmacologia , Lignanas/farmacologia , Inibidores da Angiogênese/isolamento & purificação , Animais , Pontos de Checagem do Ciclo Celular , Dioxóis/isolamento & purificação , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Lignanas/isolamento & purificação , Medicina Tradicional Tibetana , Estrutura Molecular , Compostos Fitoquímicos/isolamento & purificação , Compostos Fitoquímicos/farmacologia , Tibet , Peixe-Zebra
9.
Nat Prod Res ; 35(24): 5757-5764, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33054376

RESUMO

Two new cycloartane glycosides, cycloatriosides A and B (1-2), and a new oleanolic acid glycoside, thaliatrioside A (3), along with 7 known triterpenoids (4-10) were isolated from Thalictrum atriplex. The structures of the new compounds were established as 3-O-ß-D-galactopyranosyl (20S, 24 R)-3ß,16ß,25,29-tetrahydroxy-20,24-epoxycycloartane-29-O-ß-D-glucopyranoside (1), 3-O-ß-D-glucopyranosyl-(1→2)-α-arabinopyranosyl-3ß,22ξ,30-trihydroxycycloart-24-en-21-oic acid α-L-arabinopyranosyl-(1→6)-ß-D-glucopyranoside (2) and 3-O-[α-L-rhamnopyranosyl-(1→3)-ß-D-xylopyranosyl-(1→3)-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl]-oleanolic acid 28-O-ß-D-glucopyranosyl ester (3) on the basis of extensive NMR and HR-ESI-MS analyses, along with acid hydrolysis. Their cytotoxic activities against human lung cancer cells A549 and human breast cancer cells MDA-MB-231 were evaluated using MTT method. Compound 9 showed cytotoxicity against MDA-MB-231 cell line with the IC50 value of 72.53 ± 1.08 µM.


Assuntos
Atriplex , Saponinas , Thalictrum , Triterpenos , Glicosídeos , Humanos , Estrutura Molecular , Saponinas/farmacologia , Triterpenos/farmacologia
10.
Braz. j. med. biol. res ; 53(11): e8930, 2020. tab
Artigo em Inglês | LILACS, Coleciona SUS | ID: biblio-1132486

RESUMO

This study aimed to investigate whether the routine administration of escitalopram for three months would improve the prognosis of patients with ischemic stroke and decrease the plasma copeptin level. A total of 97 patients with acute cerebral infarction were randomly allocated to receive escitalopram (5-10 mg once per day, orally; n=49) or not to receive escitalopram (control group; n=48) for 12 weeks starting at 2-7 days after the onset of stroke. Both groups received conventional treatments, including physiotherapy and secondary prevention of stroke. The National Institutes of Health Stroke Scale (NIHSS) score was used to evaluate the disability of patients at the initial evaluation and at the monthly follow-up visits for three months. Impairment in the daily activities was assessed using the Barthel Index (BI), while cognitive impairment was assessed using Mini-Mental State Examination (MMSE) score. The psychiatric assessment included the administration of the Present State Examination modified to identify Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) symptoms of depression. The severity of depression was measured using the 17-item Hamilton Rating Scale for Depression (HAMD). During the 3-month follow-up period, 95 patients were included in the analysis (two patients withdrew from the escitalopram group). NIHSS and BI improvement at the 90th day were significantly greater in the escitalopram group (P<0.05), while HAMD and plasma copeptin levels significantly decreased, compared to the control group (P<0.01). In patients with acute ischemic stroke, the earlier administration of escitalopram for three months may improve neurological functional prognosis and decrease copeptin level.


Assuntos
Humanos , Infarto Cerebral/tratamento farmacológico , Isquemia Encefálica , Acidente Vascular Cerebral/prevenção & controle , Acidente Vascular Cerebral/tratamento farmacológico , Estados Unidos , Citalopram/uso terapêutico , Infarto Cerebral/prevenção & controle , Doença Aguda
11.
Proc Natl Acad Sci U S A ; 113(22): E3111-9, 2016 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-27185912

RESUMO

Hemagglutinin-esterases (HEs) are bimodular envelope proteins of orthomyxoviruses, toroviruses, and coronaviruses with a carbohydrate-binding "lectin" domain appended to a receptor-destroying sialate-O-acetylesterase ("esterase"). In concert, these domains facilitate dynamic virion attachment to cell-surface sialoglycans. Most HEs (type I) target 9-O-acetylated sialic acids (9-O-Ac-Sias), but one group of coronaviruses switched to using 4-O-Ac-Sias instead (type II). This specificity shift required quasisynchronous adaptations in the Sia-binding sites of both lectin and esterase domains. Previously, a partially disordered crystal structure of a type II HE revealed how the shift in lectin ligand specificity was achieved. How the switch in esterase substrate specificity was realized remained unresolved, however. Here, we present a complete structure of a type II HE with a receptor analog in the catalytic site and identify the mutations underlying the 9-O- to 4-O-Ac-Sia substrate switch. We show that (i) common principles pertaining to the stereochemistry of protein-carbohydrate interactions were at the core of the transition in lectin ligand and esterase substrate specificity; (ii) in consequence, the switch in O-Ac-Sia specificity could be readily accomplished via convergent intramolecular coevolution with only modest architectural changes in lectin and esterase domains; and (iii) a single, inconspicuous Ala-to-Ser substitution in the catalytic site was key to the emergence of the type II HEs. Our findings provide fundamental insights into how proteins "see" sugars and how this affects protein and virus evolution.


Assuntos
Coronavirus/enzimologia , Hemaglutininas Virais/metabolismo , Lectinas/metabolismo , Mutação/genética , Receptores Virais/metabolismo , Ácidos Siálicos/metabolismo , Proteínas Virais de Fusão/metabolismo , Animais , Sítios de Ligação , Domínio Catalítico , Colo/metabolismo , Cristalografia por Raios X , Hemaglutininas Virais/química , Hemaglutininas Virais/genética , Humanos , Lectinas/química , Camundongos , Simulação de Acoplamento Molecular , Receptores de Coronavírus , Receptores Virais/química , Receptores Virais/genética , Ácidos Siálicos/química , Estereoisomerismo , Especificidade por Substrato , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/genética
12.
PLoS Pathog ; 8(1): e1002492, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22291594

RESUMO

The hemagglutinin-esterases (HEs), envelope glycoproteins of corona-, toro- and orthomyxoviruses, mediate reversible virion attachment to O-acetylated sialic acids (O-Ac-Sias). They do so through concerted action of distinct receptor-binding ("lectin") and receptor-destroying sialate O-acetylesterase ("esterase") domains. Most HEs target 9-O-acetylated Sias. In one lineage of murine coronaviruses, however, HE esterase substrate and lectin ligand specificity changed dramatically as these viruses evolved to use 4-O-acetylated Sias instead. Here we present the crystal structure of the lectin domain of mouse hepatitis virus (MHV) strain S HE, resolved both in its native state and in complex with a receptor analogue. The data show that the shift from 9-O- to 4-O-Ac-Sia receptor usage primarily entailed a change in ligand binding topology and, surprisingly, only modest changes in receptor-binding site architecture. Our findings illustrate the ease with which viruses can change receptor-binding specificity with potential consequences for host-, organ and/or cell tropism, and for pathogenesis.


Assuntos
Hemaglutininas Virais/química , Vírus da Hepatite Murina/química , Ácido N-Acetilneuramínico/química , Receptores Virais/química , Proteínas Virais de Fusão/química , Animais , Sítios de Ligação , Cristalografia por Raios X , Hemaglutininas Virais/metabolismo , Humanos , Camundongos , Vírus da Hepatite Murina/fisiologia , Ácido N-Acetilneuramínico/metabolismo , Ratos , Ratos Wistar , Receptores Virais/metabolismo , Proteínas Virais de Fusão/metabolismo , Tropismo Viral/fisiologia
13.
Tumori ; 97(2): 203-10, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21617716

RESUMO

AIMS AND BACKGROUND: Cystatin C is a member of the cysteine protease inhibitors and its function is to decrease protease activity. A recent study showed that it was aberrantly expressed in many malignant tumors in association with tumor invasion and metastasis. We attempted to detect its expression in esophageal cancer tissues and adjacent reparative normal tissues. METHODS AND DESIGN: Samples of cancers and non-cancerous esophageal tissues were obtained as matched pairs from 30 surgery patients with esophageal cancer and paraffin embedded. The expression of cystatin C in tissues was investigated by immunohistochemistry. Fisher's exact test was used to analyze the relationship between esophageal cancer tissues and adjacent normal tissues. Furthermore, mRNA was extracted, and reverse transcriptase polymerase chain reaction was performed. RESULTS: The intensity of cystatin C immunostaining in tumor tissues was increased compared to that of adjacent normal tissues. mRNA expression of the cystatin C gene was greater in esophageal cancer than in normal tissues (P <0.05). CONCLUSIONS: Our results indicate that cystatin C may play an important role in the pathogenesis and metastasis of esophageal cancer.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma de Células Escamosas/metabolismo , Cistatina C/metabolismo , Neoplasias Esofágicas/metabolismo , Adulto , Idoso , Cistatina C/genética , Cistatina C/imunologia , Esôfago/metabolismo , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
14.
Mol Med Rep ; 3(4): 607-11, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21472286

RESUMO

Cystatin C is a member of the cysteine protease inhibitor family and functions to decrease protease production. A recent study showed that it is aberrantly expressed in many malignant tumors in association with tumor invasion and metastasis. Our study aimed to detect Cystatin C expression in stomach neoplasm tissues and adjacent reparative normal tissues. Samples of cancerous and non-cancerous stomach tissue were obtained via surgery as matched pairs from 12 patients with stomach neoplasms and preserved in paraffin. The expression of Cystatin C in the samples was investigated by immunohistochemistry. Fisher's exact test was used to analyze the relationship between stomach neoplasms and adjacent normal tissues. Additionally, mRNA was extracted and analysed by reverse transcriptase-polymerase chain reaction. The intensity of Cystatin C immunostaining was increased in the tumor tissues compared to the adjacent normal tissues. Cystatin C mRNA expression was increased in stomach neoplasms compared to the normal tissues (p<0.05). The results indicate that the expression of Cystatin C may serve as a marker for stomach neoplasms.

15.
Proc Natl Acad Sci U S A ; 106(37): 15897-902, 2009 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-19721004

RESUMO

Hemagglutinin esterases (HEs), closely related envelope glycoproteins in influenza C and corona- and toroviruses, mediate reversible attachment to O-acetylated sialic acids (Sias). They do so by acting both as lectins and as receptor-destroying enzymes, functions exerted by separate protein domains. HE divergence was accompanied by changes in quaternary structure and in receptor and substrate specificity. The selective forces underlying HE diversity and the molecular basis for Sia specificity are poorly understood. Here we present crystal structures of porcine and bovine torovirus HEs in complex with receptor analogs. Torovirus HEs form homodimers with sialate-O-acetylesterase domains almost identical to corresponding domains in orthomyxo- and coronavirus HEs, but with unique lectin sites. Structure-guided biochemical analysis of the esterase domains revealed that a functionally, but not structurally conserved arginine-Sia carboxylate interaction is critical for the binding and positioning of glycosidically bound Sias in the catalytic pocket. Although essential for efficient de-O-acetylation of Sias, this interaction is not required for catalysis nor does it affect substrate specificity. In fact, the distinct preference of the porcine torovirus enzyme for 9-mono- over 7,9-di-O-acetylated Sias can be explained from a single-residue difference with HEs of more promiscuous specificity. Apparently, esterase and lectin pockets coevolved; also the porcine torovirus HE receptor-binding site seems to have been designed to use 9-mono- and exclude di-O-acetylated Sias, possibly as an adaptation to replication in swine. Our findings shed light on HE evolution and provide fundamental insight into mechanisms of substrate binding, substrate recognition, and receptor selection in this important class of virion proteins.


Assuntos
Hemaglutininas Virais/química , Hemaglutininas Virais/metabolismo , Torovirus/enzimologia , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/metabolismo , Substituição de Aminoácidos , Animais , Domínio Catalítico/genética , Bovinos , Cristalografia por Raios X , Dimerização , Hemaglutininas Virais/genética , Ligantes , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Estrutura Quaternária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Ácidos Siálicos/metabolismo , Especificidade da Espécie , Especificidade por Substrato , Suínos , Torovirus/genética , Proteínas Virais de Fusão/genética
16.
Proc Natl Acad Sci U S A ; 105(26): 9065-9, 2008 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-18550812

RESUMO

The hemagglutinin-esterases (HEs) are a family of viral envelope glycoproteins that mediate reversible attachment to O-acetylated sialic acids by acting both as lectins and as receptor-destroying enzymes (RDEs). Related HEs occur in influenza C, toro-, and coronaviruses, apparently as a result of relatively recent lateral gene transfer events. Here, we report the crystal structure of a coronavirus (CoV) HE in complex with its receptor. We show that CoV HE arose from an influenza C-like HE fusion protein (HEF). In the process, HE was transformed from a trimer into a dimer, whereas remnants of the fusion domain were adapted to establish novel monomer-monomer contacts. Whereas the structural design of the RDE-acetylesterase domain remained unaltered, the HE receptor-binding domain underwent remodeling to such extent that the ligand is now bound in opposite orientation. This is surprising, because the architecture of the HEF site was preserved in influenza A HA over a much larger evolutionary distance, a switch in receptor specificity and extensive antigenic variation notwithstanding. Apparently, HA and HEF are under more stringent selective constraints than HE, limiting their exploration of alternative binding-site topologies. We attribute the plasticity of the CoV HE receptor-binding site to evolutionary flexibility conferred by functional redundancy between HE and its companion spike protein S. Our findings offer unique insights into the structural and functional consequences of independent protein evolution after interviral gene exchange and open potential avenues to broad-spectrum antiviral drug design.


Assuntos
Evolução Biológica , Coronavirus/enzimologia , Coronavirus/genética , Hemaglutininas Virais/química , Orthomyxoviridae/genética , Proteínas Virais de Fusão/química , Animais , Sítios de Ligação , Bovinos , Linhagem Celular , Sequência Conservada , Cristalografia por Raios X , Hemaglutininas Virais/isolamento & purificação , Humanos , Modelos Moleculares , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Receptores Virais/metabolismo , Proteínas Recombinantes de Fusão/química , Proteínas Virais de Fusão/isolamento & purificação
17.
Arterioscler Thromb Vasc Biol ; 27(7): 1657-65, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17510465

RESUMO

OBJECTIVE: Protein misfolding diseases result from the deposition of insoluble protein aggregates that often contain fibrils called amyloid. Amyloids are found in Alzheimer disease, atherosclerosis, diabetes mellitus, and systemic amyloidosis, which are diseases where platelet activation might be implicated. METHODS AND RESULTS: We induced amyloid properties in 6 unrelated proteins and found that all induced platelet aggregation in contrast to fresh controls. Amyloid-induced platelet aggregation was independent of thromboxane A2 formation and ADP secretion but enhanced by feedback stimulation through these pathways. Treatments that raised cAMP (iloprost), sequestered Ca2+ (BAPTA-AM) or prevented amyloid-platelet interaction (sRAGE, tissue-type plasminogen activator [tPA]) induced almost complete inhibition. Modulation of the function of CD36 (CD36-/- mice), p38(MAPK) (SB203580), COX-1 (indomethacin), and glycoprotein Ib alpha (Nk-protease, 6D1 antibody) induced approximately 50% inhibition. Interference with fibrinogen binding (RGDS) revealed a major contribution of alphaIIb beta3-independent aggregation (agglutination). CONCLUSIONS: Protein misfolding resulting in the appearance of amyloid induces platelet aggregation. Amyloid activates platelets through 2 pathways: one is through CD36, p38(MAPK), thromboxane A2-mediated induction of aggregation; the other is through glycoprotein Ib alpha-mediated aggregation and agglutination. The platelet stimulating properties of amyloid might explain the enhanced platelet activation observed in many diseases accompanied by the appearance of misfolded proteins with amyloid.


Assuntos
Amiloide/farmacologia , Plaquetas/citologia , Ativação Plaquetária/efeitos dos fármacos , Ativação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/farmacologia , Plaquetas/metabolismo , Antígenos CD36/metabolismo , Células Cultivadas , Humanos , Agregação Plaquetária/fisiologia , Inibidores da Agregação Plaquetária/metabolismo , Complexo Glicoproteico GPIb-IX de Plaquetas/metabolismo , Valores de Referência , Sensibilidade e Especificidade , Tromboxano A2/metabolismo , Ativador de Plasminogênio Tecidual/metabolismo
18.
J Biol Chem ; 279(2): 1491-8, 2004 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-14573596

RESUMO

Pirin is a newly identified nuclear protein that interacts with the oncoprotein B-cell lymphoma 3-encoded (Bcl-3) and nuclear factor I (NFI). The crystal structure of human Pirin at 2.1-A resolution shows it to be a member of the functionally diverse cupin superfamily. The structure comprises two beta-barrel domains, with an Fe(II) cofactor bound within the cavity of the N-terminal domain. These findings suggest an enzymatic role for Pirin, most likely in biological redox reactions involving oxygen, and provide compelling evidence that Pirin requires the participation of the metal ion for its interaction with Bcl-3 to co-regulate the NF-kappaB transcription pathway and the interaction with NFI in DNA replication. Substitution of iron by heavy metals thus provides a novel pathway for these metals to directly influence gene transcription. The structure suggests an interesting new role of iron in biology and that Pirin may be involved in novel mechanisms of gene regulation.


Assuntos
Proteínas de Transporte/química , Núcleo Celular/metabolismo , Proteínas Nucleares/química , Sequência de Aminoácidos , Sítios de Ligação , Clonagem Molecular , Cristalografia por Raios X , DNA Complementar/metabolismo , Dioxigenases , Biblioteca Gênica , Humanos , Íons , Proteínas de Ligação ao Ferro/química , Fígado/metabolismo , Metais/química , Modelos Moleculares , Dados de Sequência Molecular , NF-kappa B/metabolismo , Oxigênio/metabolismo , Conformação Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Temperatura , Transcrição Gênica
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