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1.
The complete nucleotide sequence of the Escherichia coli gene appA reveals significant homology between pH 2.5 acid phosphatase and glucose-1-phosphatase. 总被引:3,自引:1,他引:2 下载免费PDF全文
The whole nucleotide sequence of Escherichia coli gene appA, which encodes periplasmic phosphoanhydride phosphohydrolase (optimum pH, 2.5), and its flanking regions was determined. The AppA protein is significantly homologous to the product of the nearby gene agp, acid glucose-1-phosphatase. Because identical amino acids are distributed over the whole lengths of the proteins, it is likely that appA and agp originate from the same ancestor gene. 相似文献
2.
Fresh trophoblastic preparations of two human placentae delivered at term were pulse labelled for 30, 120 and 240 min with tritiated L-tyrosine. After deproteinizing and defatting, the peptide extracts were first concentrated through reversible hydrophobic binding on octadecasilyl-silica particles, prior to further resolution by repetetive high-performance liquid chromatography. Four peptides were isolated and purified to radioactive homogeneity, namely Met-enkephalin, Leu-enkephalin, (Arg6)-Leu-enkephalin, and (Arg6, Arg7)-Leu-enkephalin. Their presence and identity were further confirmed by substractive Edman degradation and by radioimmunoassay. No detectable amounts of radioactive Dynorphin could be trapped, however. Under the incubation conditions used, reference tritiated Leu-enkephalin had a biological half-life of circa 9.5 min. 相似文献
3.
Monica Y. Burgos Zepeda Kevin Alessandri Dorothée Murat Chahrazade El Amri Elie Dassa 《Biochimica et Biophysica Acta - Proteins and Proteomics》2010,1804(4):755-761
The Uup protein belongs to a subfamily of soluble ATP-binding cassette (ABC) ATPases that have been implicated in several processes different from transmembrane transport of molecules, such as transposon precise excision. We have demonstrated previously that Escherichia coli Uup is able to bind DNA. DNA binding capacity is lowered in a truncated Uup protein lacking its C-terminal domain (CTD), suggesting a contribution of CTD to DNA binding. In the present study, we characterize the role of CTD in the function of Uup, on its overall stability and in DNA binding. To this end, we expressed and purified isolated CTD and we investigated the structural and functional role of this domain. The results underline that CTD is essential for the function of Uup, is stable and able to fold up autonomously. We compared the DNA binding activities of three versions of the protein (Uup, UupΔCTD and CTD) by an electrophoretic mobility shift assay. CTD is able to bind DNA although less efficiently than intact Uup and UupΔCTD. These observations suggest that CTD is an essential domain that contributes directly to the DNA binding ability of Uup. 相似文献
4.
Galina Feinberg-Gorenshtein Avital Guedj Keren Shichrur Marta Jeison Drorit Luria Yona Kodman Shifra Ash Meora Feinmesser Liat Edry Noam Shomron Abraham Weizman Isaac Yaniv Smadar Avigad 《PloS one》2013,8(11)
Neuroblastoma (NB) arises from the embryonic neural crest and is the most common extracranial solid tumor in children under 5 years of age. Reduced expression of Dicer1 has recently been shown to be in correlation with poor prognosis in NB patients. This study aimed to investigate the mechanisms that could lead to the down-regulation of Dicer1 in neuroblastoma. We used computational prediction to identify potential miRs down-regulating Dicer1 in neuroblastoma. One of the miRs that were predicted to target Dicer1 was miR-192. We measured the levels of miR-192 in 43 primary tumors using real time PCR. Following the silencing of miR-192, the levels of dicer1 cell viability, cell proliferation and migration capability were analyzed. Multivariate analysis identified miR-192 as an independent prognostic marker for relapse in neuroblastoma patients (p=0.04). We were able to show through a dual luciferase assay and side-directed mutational analysis that miR-192 directly binds the 3'' UTR of Dicer1 on positions 1232-1238 and 2282-2288. An increase in cell viability, proliferation and migration rates were evident in NB cells transfected with miR-192-mimic. Yet, there was a significant decrease in proliferation when NB cells were transfected with an miR-192-inhibitor We suggest that miR-192 might be a key player in NB by regulating Dicer1 expression. 相似文献
5.
6.
Escherichia coli (thyA DeltafolA) mutants are viable and can grow in minimal medium when supplemented with thymidine alone. Here we present evidence from in vivo and in vitro studies that the ydgB gene determines an alternative dihydrofolate reductase that is related to the trypanosomatid pteridine reductases. We propose to rename this gene folM. 相似文献
7.
Inbar Shlomovitz Ziv Erlich Gali Arad Liat Edry-Botzer Sefi Zargarian Hadar Cohen Tal Manko Yifat Ofir-Birin Tomer Cooks Neta Regev-Rudzki Motti Gerlic 《Cell death & disease》2021,12(11)
Necroptosis is a regulated and inflammatory form of cell death. We, and others, have previously reported that necroptotic cells release extracellular vesicles (EVs). We have found that necroptotic EVs are loaded with proteins, including the phosphorylated form of the key necroptosis-executing factor, mixed lineage kinase domain-like kinase (MLKL). However, neither the exact protein composition, nor the impact, of necroptotic EVs have been delineated. To characterize their content, EVs from necroptotic and untreated U937 cells were isolated and analyzed by mass spectrometry-based proteomics. A total of 3337 proteins were identified, sharing a high degree of similarity with exosome proteome databases, and clearly distinguishing necroptotic and control EVs. A total of 352 proteins were significantly upregulated in the necroptotic EVs. Among these were MLKL and caspase-8, as validated by immunoblot. Components of the ESCRTIII machinery and inflammatory signaling were also upregulated in the necroptotic EVs, as well as currently unreported components of vesicle formation and transport, and necroptotic signaling pathways. Moreover, we found that necroptotic EVs can be phagocytosed by macrophages to modulate cytokine and chemokine secretion. Finally, we uncovered that necroptotic EVs contain tumor neoantigens, and are enriched with components of antigen processing and presentation. In summary, our study reveals a new layer of regulation during the early stage of necroptosis, mediated by the secretion of specific EVs that influences the microenvironment and may instigate innate and adaptive immune responses. This study sheds light on new potential players in necroptotic signaling and its related EVs, and uncovers the functional tasks accomplished by the cargo of these necroptotic EVs.Subject terms: Necroptosis, Cell death and immune response 相似文献
8.
Daus ML Grote M Müller P Doebber M Herrmann A Steinhoff HJ Dassa E Schneider E 《The Journal of biological chemistry》2007,282(31):22387-22396
We have investigated conformational changes of the purified maltose ATP-binding cassette transporter (MalFGK(2)) upon binding of ATP. The transport complex is composed of a heterodimer of the hydrophobic subunits MalF and MalG constituting the translocation pore and of a homodimer of MalK, representing the ATP-hydrolyzing subunit. Substrate is delivered to the transporter in complex with periplasmic maltose-binding protein (MalE). Cross-linking experiments with a variant containing an A85C mutation within the Q-loop of each MalK monomer indicated an ATP-induced shortening of the distance between both monomers. Cross-linking caused a substantial inhibition of MalE-maltose-stimulated ATPase activity. We further demonstrated that a mutation affecting the "catalytic carboxylate" (E159Q) locks the MalK dimer in the closed state, whereas a transporter containing the "ABC signature" mutation Q140K permanently resides in the resting state. Cross-linking experiments with variants containing the A85C mutation combined with cysteine substitutions in the conserved EAA motifs of MalF and MalG, respectively, revealed close proximity of these residues in the resting state. The formation of a MalK-MalG heterodimer remained unchanged upon the addition of ATP, indicating that MalG-EAA moves along with MalK during dimer closure. In contrast, the yield of MalK-MalF dimers was substantially reduced. This might be taken as further evidence for asymmetric functions of both EAA motifs. Cross-linking also caused inhibition of ATPase activity, suggesting that transporter function requires conformational changes of both EAA motifs. Together, our data support ATP-driven MalK dimer closure and reopening as crucial steps in the translocation cycle of the intact maltose transporter and are discussed with respect to a current model. 相似文献
9.
Cohen E Koch L Thu KM Rahamim Y Aluma Y Ilan M Yarden O Carmeli S 《Bioorganic & medicinal chemistry》2011,19(22):6587-6593
Three novel meroterpenoids, insuetolides A-C (1-3) and four drimane sesquiterpenes, the new (E)-6-(4'-hydroxy-2'-butenoyl)-strobilactone A (4) and the known 2α, 9α, 11-trihydroxy-6-oxodrim-7-ene (5), strobilactone A (6) and (E,E)-6-(6',7'-dihydroxy-2',4'-octadienoyl)-strobilactone A (7), were isolated from the EtOAc extract of the culture medium of the marine-derived fungus Aspergillus insuetus (OY-207), which was isolated from the Mediterranean sponge Psammocinia sp. The structures of the compounds were determined by spectroscopic methods. Insuetolides A-C reveal a new carbon skeleton derived from the cyclization of farnesyl and 3, 5-dimethylorsellinic acid. Compounds 1, 6, and 7 exhibited anti-fungal activity towards Neurospora crassa with MIC values of 140, 242, and 162 μM, respectively; and compounds 3, 4, and 7 exhibited mild cytotoxicity towards MOLT-4 human leukemia cells. 相似文献
10.
Tobias Strunk Melanie R. Power Coombs Andrew J. Currie Peter Richmond Douglas T. Golenbock Liat Stoler-Barak Leighanne C. Gallington Michael Otto David Burgner Ofer Levy 《PloS one》2010,5(4)