Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 62
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Surg Endosc ; 2019 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-31664578

RESUMO

BACKGROUND: Radical resection is the only curative option for patients with hilar cholangiocarcinoma (HCCA) to achieve long-term survival. However, due to the fact that radical resection of HCCA has high technical requirements, the safety and efficacy of laparoscopic resection for HCCA remains controversial. METHOD: From January 2015 to December 2018, 23 cases of HCCA underwent radical resection in our center. Clinical data of those patients were collected and analyzed retrospectively. RESULTS: 14 patients underwent laparoscopic resection and 9 cases received open resection. 2 patients in laparoscopic group were converted to laparotomy. Operation time in laparoscopic group was significantly longer than that in open group (519.4 ± 155.4 min vs 366.7 ± 93.1 min). Estimated blood loss (620.0 ± 681.2 ml vs 821.4 ± 713.8 ml) and incidence of intraoperative blood transfusion (5/9 vs 8/14) did not differ significantly between two groups. Pathological outcomes were comparable between two groups. Length of postoperative hospital stay (23.4 ± 13.4 days vs 17.8 ± 7.1 days), severe postoperative morbidity (3/9 vs 5/14), bile leakage of Grade A or B (5/9 vs 5/14), intra-abdominal bleeding (0/9 vs 1/14), intra-abdominal abscess (1/9 vs 0/14), wound infection (0/9 vs 1/14), pulmonary infection (2/9 vs 0/14), and liver failure (0/9 vs 0/14) did not differ significantly between two groups. One patient in laparoscopic group died (1/14) at 21 postoperative days due to intra-abdominal bleeding, while no 30-day mortality was observed in open group. CONCLUSION: Our results demonstrate that laparoscopic radical resection of HCCA is safe and feasible in experienced hands. Although laparoscopic resection for HCCA, which is still in initial and exploratory stage, fails to show any advantage over open resection in this study, we are optimistic with its wide application in future with the improvement of surgical techniques and experience.

2.
Biosci Trends ; 13(5): 456-460, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31611521

RESUMO

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is no longer a rarely diagnosed disease, because of the development of medical imaging. With a high incidence of canceration, especially in the main duct type, surgery is strongly recommended. Pancreatoduodenectomy, distal pancreatectomy and central pancreatectomy are applied in those cases. For this potentially malignant disease, function-preserving surgery seems more appropriate. An old female was enrolled in our research, who was diagnosed with IPMN. Diameter of the main pancreatic duct (MPD) was > 5 mm and lesions distributed to the whole pancreas. laparoscopic duodenum and spleen-preserving total pancreatoduodenectomy was carried out, which has not reported previously. We successfully performed laparoscopic duodenum and spleen-preserving total pancreatectomy, without major complications such as severe pancreatic fistula, postoperative bleeding, and delayed ischemia of duodenum and spleen. We consider laparoscopic duodenum and spleen-preserving total pancreatectomy is technically feasible, but a large sample of randomized controlled trials is needed to evaluate its safety, effectiveness and long-term outcome.

3.
Chin J Traumatol ; 22(5): 308-310, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31371236

RESUMO

Systemic air embolism is a rare but potentially fatal complication related to many factors. The purpose of this article is to alert clinicians once patients occurs an abnormal neurological and cardiovascular status, following minor traumatic treatment, air embolism should be considered. A 20-year-old man who presented with fungal pneumonia with lung cavities formation was admitted to an intensive care unit (ICU) and received positive airway pressure ventilation. Four days later, the fungal pneumonia was improved, but the patient's blood pressure and arterial oxygen saturation deteriorated, so computed tomography (CT) scans were preformed to reevaluate him. The scans detected air embolism in the left atrium and ventricle, ascending aorta, aortic arch and its branches (right brachiocephalic, bilateral common carotid and right subclavian arteries), descending aorta and right coronary artery. A CT scan of the abdomen revealed air in the spleen, cauda pancreatic, superior mesenteric artery and right external iliac artery. The patient died two days later from multiple organ dysfunction. We suggest that vascular air embolism should be considered under mechanical ventilation when patients' neurologic and cardiovascular status deteriorates, and hyperbaric oxygen therapy should be conducted immediately.

4.
Artigo em Inglês | MEDLINE | ID: mdl-31279678

RESUMO

This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

5.
J Environ Manage ; 245: 168-172, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31152960

RESUMO

The biorestoration of cyhalofop-butyl and fertility in soil using Rhodopseudanonas palustris (R. palustris) in the treated wastewater were investigated in this research. Cyhalofop-butyl was not degraded under control group. The treated wastewater containing R. palustris degraded cyhalofop-butyl and remediated fertility. Interestingly, the cyhalofop-butyl-hydrolyzing carboxylesterase gene was expressed after inoculation 24 h. Subsequently, the cyhalofop-butyl-hydrolyzing carboxylesterase were synthesized to degrade cyhalofop-butyl. The cyhalofop-butyl started to be degraded after inoculation 24 h. The cyhalofop-butyl as stimulus signal induced cyhalofop-butyl-hydrolyzing carboxylesterase gene expression through signal transduction pathway. This process took 24 h for R. palustris as they were ancient bacteria. The residual organics in the wastewater provided sufficient carbon sources and energy for R. palustris under three dosage groups. The new method completed the remediation of cyhalofop-butyl pollution, the improvement of soil fertility and soybean processing wastewater treatment simultaneously, and realized the resource reutilization of wastewater and R. palustris as sludge.


Assuntos
Herbicidas , Águas Residuárias , Butanos , Nitrilos , Solo
6.
Chemosphere ; 233: 597-602, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195264

RESUMO

Carbaryl wastewater treatment and the resource recycling of biomass as sludge by Rhodopseudomonas sphaeroides (R. sphaeroides) with the assistance of starch processing wastewater (SPW) was investigated in this research. It was observed that carbaryl was not degraded under the 100, 500 mg/L COD groups. The addition of SPW assisted R. sphaeroides to degrade carbaryl efficiently. Carbaryl removal reached 100% after 5 days under the optimal group (3500 mg/L). Interestingly, carbaryl in the mixed wastewater began to be degraded after day 1. Further research indicated that cehA gene was expressed after day 1. Subsequently, carbaryl hydrolase was synthesized under gene regulation. Analysis revealed that cehA and carbaryl hydrolase were adaptive gene expressions and enzymes. Carbaryl as stimulus signal started cehA gene expression through signal transduction pathway. This process took one day for R. sphaeroides. However, organics in 100, 500 mg/L COD groups were deficient, which could not maintain R. sphaeroides growth for over one day. Organics in SPW provided sufficient carbon sources for R. sphaeroides under other groups. The method could complete the mixed (SPW and carbaryl) wastewater treatment, carbaryl removal, the resource recycling of R. sphaeroides biomass as sludge simultaneously.


Assuntos
Carbaril/metabolismo , Rhodobacter sphaeroides/metabolismo , Eliminação de Resíduos Líquidos/métodos , Biodegradação Ambiental , Biomassa , Esgotos , Águas Residuárias/microbiologia , Purificação da Água
7.
Nanoscale ; 11(19): 9457-9467, 2019 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-31042245

RESUMO

Multifunctional nanodrugs with the integration of precise diagnostic and effective therapeutic functions have shown great promise in improving the efficacy of cancer therapy. We report herein a simple and effective approach to directly assemble an anticancer drug (curcumin), a photodynamic agent (Ce6) and tumor environment-sensitive molecules into cross-linked polyphosphazene and coat on superparamagnetic Fe3O4 nanoclusters to form discrete nanoparticles (termed as FHCPCe NPs). FHCPCe NPs have high physiological stability and good biocompatibility, and can enhance accumulation in tumor tissue via the enhanced permeability and retention effect. Meanwhile, the FHCPCe NPs exhibit an effective performance of dual-modality magnetic resonance imaging (MRI) due to the Fe3O4 cores and fluorescence imaging (FL) in the xenografted HeLa tumor because of the fluorescence of Ce6. Importantly, under the conditions of supernormal glutathione levels and acidic microenvironment in tumor tissue, curcumin and Ce6 can be effectively released by the degradation of FHCPCe NPs. Therefore, excellent anti-tumor effects both in vitro and in vivo have been achieved by synergistic chemotherapy/photodynamic therapy (CT/PDT) using multifunctional NPs. Our study highlights the promise of developing multifunctional nanomaterials for accurate multimodal imaging-guided highly sensitive therapy of cancer.

8.
Prep Biochem Biotechnol ; 49(2): 151-157, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30712466

RESUMO

Acylase AiiO is a novel quorum quenching enzyme with a broad substrate spectrum of acyl-homoserine lactones (AHLs) and has promising prospects in pathogen control. In this work, acylase AiiO production by a recombinant E. coli strain and its characterization were investigated; the acylase powder was further prepared and evaluated for effectiveness. A strategy of auto-induction combined with temperature regulation was developed to improve AiiO production. For the soluble AiiO protein in the cells, maximum production of 214.3 ± 9.4 mg/L was obtained in the fermenter. The purified acylase displayed an obvious AHL-degrading specific activity of 19.2 ± 0.56 U/mg. Sucrose, as the protective agent, maintained good stability of the acylase powder, in which the acylase remained 89.6 and 71.9% of its initial specific activity after storage at 4 °C for 3 and 6 months, respectively. The acylase powder could prominently decrease the expression levels of virulence-related factors of Pseudomonas aeruginosa. Based on the high-yield production and effective powder preparation, the quorum quenching acylase AiiO has the potential to be used in the clinical treatments of pathogenic infections.


Assuntos
Acil-Butirolactonas/metabolismo , Amidoidrolases/metabolismo , Proteínas de Bactérias/metabolismo , Ochrobactrum/metabolismo , Amidoidrolases/genética , Amidoidrolases/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/farmacologia , Clonagem Molecular , Estabilidade Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Fermentação , Humanos , Ochrobactrum/genética , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Percepção de Quorum/efeitos dos fármacos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacologia
9.
Turk J Gastroenterol ; 30(4): 364-371, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30666971

RESUMO

BACKGROUND/AIMS: The aim of present study was to assess the protective effects of Shenfu injection (SI) on the intestinal mucosa and its regulation on the mucosal immune responses in rats with sepsis. MATERIALS AND METHODS: Sprague-Dawley rats were randomly divided into the sham, model, low-dose SI (LSF), and high-dose SI (HSF) groups. Sham animals underwent laparotomy only, whereas sepsis was modeled by cecal ligation and puncture in the remaining groups. At 2 h post-surgery, the LSF and HSF groups were intraperitoneally administered 5 and 20 mL/kg SI, respectively, whereas other animals with saline. At 12 h and 24 h post-surgery, eight rats per group were sacrificed, and blood and intestinal tissues were collected. The intestinal mucosa was analyzed by hematoxylin and eosin staining. Serum tumor necrosis factor (TNF)-α and interleukin (IL)-6 concentrations, as well as secretory immunoglobulin A (sIgA) content in the intestinal mucosa, were evaluated by enzyme-linked immunosorbent assay. CD3 and γδT lymphocytes were quantified by flow cytometry. Animal survival until 72 h was also recorded. RESULTS: Intestinal mucosal injury was significantly higher in model animals than in sham animals at postoperative 12 h and 24 h. Serum TNF-α and IL-6 levels were markedly increased, whereas sIgA and CD3 and γδT cell amounts were overtly decreased (p<0.01). The LSF and HSF rats showed lower mortality, intestinal mucosal injury, and serum TNF-α and IL-6 levels (p<0.05), as well as higher sIgA levels and CD3 and γδT cell amounts, than the model group (p<0.01), with a dose-dependent manner. CONCLUSION: SI dose-dependently prolongs survival and protects the intestinal mucosa in rats with sepsis, possibly through strengthening innate immunity instead of acquired immunity.

10.
Biochemistry ; 57(42): 6054-6060, 2018 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-30252448

RESUMO

Catabolite control protein E (CcpE) is a LysR-type transcriptional regulator that positively regulates the transcription of the first two enzymes of the TCA cycle, namely, citZ and citB, by sensing accumulated intracellular citrate. CcpE comprises an N-terminal DNA-binding domain and a C-terminal regulatory domain (RD) and senses citrate with conserved arginine residues in the RD. Although the crystal structure of the apo SaCcpE-RD has been reported, the citrate-responsive and DNA-binding mechanisms by which CcpE regulates TCA activity remain unclear. Here, we report the crystal structure of the apo and citrate-bound SaCcpE-RDs. The SaCcpE-RD exhibits conformational changes between the two subdomains via hinge motion of the central ß4 and ß10 strands. The citrate molecule is located in a positively charged cavity between the two subdomains and interacts with the highly conserved Ser98, Leu100, Arg145, and Arg256 residues. Compared with that of the apo SaCcpE-RD, the distance between the two subdomains of the citrate-bound SaCcpE-RD is more than ∼3 Å due to the binding of the citrate molecule, and this form exhibits a closed structure. The SaCcpE-RD exhibits various citrate-binding-independent conformational changes at the contacting interface. The SaCcpE-RD prefers the dimeric state in solution, whereas the SaCcpE-FL prefers the tetrameric state. Our results provide insight into the molecular function of SaCcpE.

11.
Biochem Biophys Res Commun ; 503(4): 2906-2911, 2018 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-30107912

RESUMO

The nicotinamidase/pyrazinamidase PncA is a member of a large family of hydrolase enzymes that catalyze the deamination of nicotinamide to nicotinic acid. PncA also functions as a pyrazinamidase in a wide variety of eubacteria and is an essential coenzyme in many cellular redox reactions in living systems. We report the crystal structure of substrate-free PncA from Bacillus subtilis (BsPncA) at 2.0 Šresolution to improve our understanding of the PncA family. The structure of BsPncA consists of an α/ß domain and a subdomain. The subdomain of BsPncA has a different conformation than that of PncA enzymes from other organisms. The B-factor analysis revealed a rigid structure of the α/ß domain, while the subdomain is highly flexible. Both dimers and tetramers were observed in BsPncA protein crystals, but only dimers were observed in solution. Our results provide useful information that will further enhance our understanding of the molecular functions of PncA family members.

12.
Adv Mater ; 30(17): e1705670, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29527751

RESUMO

Among the various energy-storage systems, lithium-ion capacitors (LICs) are receiving intensive attention due to their high energy density, high power density, long lifetime, and good stability. As a hybrid of lithium-ion batteries and supercapacitors, LICs are composed of a battery-type electrode and a capacitor-type electrode and can potentially combine the advantages of the high energy density of batteries and the large power density of capacitors. Here, the working principle of LICs is discussed, and the recent advances in LIC electrode materials, particularly activated carbon and lithium titanate, as well as in electrolyte development are reviewed. The charge-storage mechanisms for intercalative pseudocapacitive behavior, battery behavior, and conventional pseudocapacitive behavior are classified and compared. Finally, the prospects and challenges associated with LICs are discussed. The overall aim is to provide deep insights into the LIC field for continuing research and development of second-generation energy-storage technologies.

13.
Sheng Wu Gong Cheng Xue Bao ; 34(2): 235-245, 2018 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-29424137

RESUMO

Cyclic lipopeptide has extensive application prospect in the field of medicine due to its unique chemical structure and biological activity. This study aims to obtain high purity of cyclic lipopeptide monomer from Bacillus amyloliquefaciems strain Q-426, and illuminate preliminary antitumor mechanism of C-15 Bacillomycin D and C-16 Bacillomycin D. Firstly, crude cyclic lipopeptide solution was prepared by two-steps purification of acid precipitation and double-resins chromatography. In order to obtain purer product preparative HPLC was utilized to separate and purify cyclic lipopeptide. Component 1 and component 2 were detected as C-15 Bacillomycin D and C-16 Bacillomycin D by HPLC-MS and ESI-MS/MS. Secondly, the effect of C-15 Bacillomycin D, C-16 Bacillomycin D and their mixture (1:1, mol:mol) on cell proliferation was measured using human cancer cells (Hela, MG, Hep-G2 and HT-29). The cyclic peptide showed a dose dependent manner on the cell proliferation inhibition of Hela and MG cells. Finally, the results of the scratch wound healing assay and FACS analysis revealed that C-16 Bacillomycin D can effectively influence the cells migration and the cells treated with C-16 Bacillomycin D showed typical apoptotic morphology with the increase of drug concentration in the early apoptosis, late apoptosis percentage increased, and G0G1 arrest was induced significantly.

14.
J Biotechnol ; 268: 53-60, 2018 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-29355813

RESUMO

Autoinducer-2 (AI-2) is a major signal molecule in bacterial quorum sensing (QS) besides N-acyl homoserine lactones (AHLs or AI-1). AI-2 mediated QS pathways have been proved to regulate gene expression and physiological behaviors of bacteria in either intraspecies or interspecies communication. Recent reviews have mainly summarized AI-2 structures, AI-2 mediated QS pathways and the role of AI-2 in gene regulation, etc. In this article, we present a comprehensive review of AI-2 production, detection and applications. Firstly, intracellular AI-2 synthetic routes were outlined and environmental influences on AI-2 production were focused. Furthermore, recent advances in AI-2 detection and quantification were elucidated from an overall perspective. An in-depth understanding of mechanisms and features of various detection methods may facilitate development of new technologies aimed at signal molecule detection. Finally, utilization of AI-2 mediated QS in health improvement, water treatment and drug production indicate promising and extensive application perspectives of QS strategies.


Assuntos
Bactérias/metabolismo , Homosserina/análogos & derivados , Percepção de Quorum , Técnicas Biossensoriais , Meio Ambiente , Engenharia Genética , Homosserina/biossíntese , Lactonas
15.
Hepatobiliary Pancreat Dis Int ; 16(3): 236-244, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28603091

RESUMO

BACKGROUND: Pancreatic cancer is one of the most aggressive malignancies and chemotherapy is an effective strategy for advanced pancreatic cancer. Gemcitabine (GEM) is one of first-line agents. However, GEM-based combination therapy has shown promising efficacy in patients with advanced pancreatic cancer. This meta-analysis aimed to compare the efficacy and safety of GEM-based combination therapy versus GEM alone in the treatment of advanced pancreatic cancer. DATA SOURCES: A comprehensive search of literature was performed using PubMed, EMBASE, Web of Science and Cochrane Central Register of Controlled Trials. A quantitative meta-analysis was performed based on the inclusion criteria from all eligible randomized controlled trials. The outcome indicators included overall survival (OS), 6-month survival, 1-year survival, progression-free survival/time-to-progression (PFS/TTP), and toxicities. RESULTS: A total of nine randomized controlled trials involving 1661 patients were included in this meta-analysis. There was significant improvement in the GEM-based combination therapy with regard to the OS (HR=0.85, 95% CI: 0.76-0.95, P=0.003), PFS (HR=0.76, 95% CI: 0.65-0.90, P=0.002), 6-month survival (RR=1.09, 95% CI: 1.01-1.17, P=0.03), and the overall toxicity (RR=1.68, 95% CI: 1.52-1.86, P<0.01). However, there was no significant difference in the 1-year survival. CONCLUSIONS: GEM-based combination chemotherapy might improve the OS, 6-month survival, and PFS in advanced pancreatic cancer. However, combined therapy also added toxicity.


Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxicitidina/análogos & derivados , Neoplasias Pancreáticas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Antimetabólitos Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Distribuição de Qui-Quadrado , Desoxicitidina/efeitos adversos , Desoxicitidina/uso terapêutico , Progressão da Doença , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Neoplasias Pancreáticas/mortalidade , Neoplasias Pancreáticas/patologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
16.
Oncol Lett ; 12(2): 1623-1629, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27446483

RESUMO

Autophagy can protect cells from stress, but can also induce cancer cell death. Caspase-10 is now considered to be a factor that is associated with autophagy in cancer. The present study therefore investigated whether caspase-10 affects autophagy in acute leukemia cells. The rates of survival vs. apoptosis in acute leukemia HL-60 and Jurkat cells treated with drugs were tested using cell viability assays and flow cytometry, and the levels of caspase-3 and -10 were tested by western blotting. In HL-60 cells that were treated with chemotherapy drugs combined with a caspase-10 inhibitor, the rate of survival decreased significantly compared with HL-60 cells treated with chemotherapy drugs alone. In contrast, the rate of survival of Jurkat cells treated with chemotherapy drugs combined with the caspase-10 inhibitor increased significantly compared with Jurkat cells treated with chemotherapy drugs alone. The results of the flow cytometry and western blotting showed that the changes in the survival rate may be caused by a change in the amount of apoptosis occurring in the Jurkat cells treated with chemotherapy drugs combined with the caspase-10 inhibitor. However, in HL-60 cells undergoing this combination treatment, the change in the survival rate was not caused by a change in the rate of apoptosis. When HL-60 cells were treated with the chemotherapy drugs combined with the caspase-10 inhibitor and the autophagy inhibitor 3-methyl adenine, the survival rate increased, whereas the rate of apoptosis did not change. These results show that caspase-10 may be associated with autophagy in acute myeloid leukemia cells, but not in acute lymphatic leukemia cells.

17.
Mar Drugs ; 14(4)2016 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-27110799

RESUMO

In recent years, a considerable number of structurally unique metabolites with biological and pharmacological activities have been isolated from the marine-derived fungi, such as polyketides, alkaloids, peptides, lactones, terpenoids and steroids. Some of these compounds have anticancer, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, antibiotic and cytotoxic properties. This review partially summarizes the new bioactive compounds from marine-derived fungi with classification according to the sources of fungi and their biological activities. Those fungi found from 2014 to the present are discussed.


Assuntos
Produtos Biológicos/metabolismo , Produtos Biológicos/farmacologia , Fungos/metabolismo , Animais , Humanos
18.
J Biosci Bioeng ; 121(2): 242-6, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26560241

RESUMO

AgrC is an integral membrane receptor protein with histidine kinase activity in the accessory gene regulator (agr) quorum-sensing system of Staphylococcus aureus. In this study, proteoliposomes were used as a model to investigate AgrC orientation. Many approaches have been described to determine membrane protein orientation, but they are often complicated and time consuming. In this study, AgrC orientation in liposomes was determined by thiol-reactive reagent labeling and a kinase activity assay. Our results suggest use of a kinase activity assay could get an accurate percentage of functional protein orientation and only cost nearly one-sixth of the time compared with the method based on thiol-reactive reagent labeling. We present an effective and rapid method for determining the orientation of membrane protein kinases like AgrC.


Assuntos
Proteínas de Bactérias/metabolismo , Biocatálise , Ensaios Enzimáticos , Proteínas de Membrana/metabolismo , Proteínas Quinases/metabolismo , Staphylococcus aureus/enzimologia , Proteínas de Bactérias/análise , Proteínas de Membrana/análise , Fosforilação , Proteínas Quinases/análise , Proteolipídeos/metabolismo , Percepção de Quorum , Compostos de Sulfidrila/química , Fatores de Tempo
19.
Acta Crystallogr F Struct Biol Commun ; 71(Pt 4): 393-6, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25849497

RESUMO

Prokaryotic 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (MtaN) is a multifunctional enzyme that can hydrolyze S-adenosyl-L-homocysteine (SAH) and S-methyl-5'-thioadenosine (MTA) to give S-ribosyl-L-homocysteine (SRH) and S-methyl-5'-thioribose (MTR), respectively. This reaction plays a key role in several metabolic pathways, including biological methylation, polyamine biosynthesis, methionine recycling and bacterial quorum sensing. Structurally, MtaN belongs to the MtnN subfamily of the purine nucleoside phosphorylase (PNP)/uridine phosphorylase (UDP) phosphorylase family. Aeromonas hydrophila has two MtnN subfamily proteins: MtaN-1, a periplasmic protein with an N-terminal signal sequence, and MtaN-2, a cytosolic protein. In this study, MtaN-1 from Aeromonas hydrophila was successfully expressed and purified using Ni-NTA affinity, Q anion-exchange and gel-filtration chromatography. Crystals of the protein in complex with the substrate SAH were obtained and diffracted to a resolution of 1.4 Å. The crystals belonged to the trigonal space group P3121 or P3221, with unit-cell parameters a = b = 102.7, c = 118.8 Å. The asymmetric unit contained two molecules of MtaN-1 complexed with SAH.


Assuntos
Aeromonas hydrophila/enzimologia , N-Glicosil Hidrolases/química , N-Glicosil Hidrolases/metabolismo , S-Adenosil-Homocisteína/química , S-Adenosil-Homocisteína/metabolismo , Cristalização , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA