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E Protein (e + protein)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Bacterial cell death induced by human pro-apoptotic Bax is blocked by an RNase E mutant that functions in an anti-oxidant pathway

GENES TO CELLS, Issue 3 2000
Rika Nanbu-Wakao
Background Bax is a member of the Bcl-2 family and induces apoptosis of mammalian cells. We have shown that a trace amount of human Bax induces the cell death of Escherichia coli, accompanied by damage to DNA, and that the region of Bax which is lethal to E. coli is also responsible for apoptosis-inducing activity in the mammalian cells. Results We isolated a Bax-resistant mutant from E. coli cells that survive in the presence of paraquat, a generator of superoxide, by screening a library constructed from the random insertion of a transposon. Psb1 (paraquat-resistant, suppressor of Bax-1) mutant had a Tn 10 transposon inserted in the rne gene of E. coli, splitting the RNase E gene (rne) into N- and C-terminal halves. The introduction of the truncated 5, end of rne specifically enhanced resistance to paraquat, prevented cell death induced by Bax and decreased the intracellular H2O2 concentration. The region responsible for the paraquat- and Bax-resistance was not the catalytic site for the endoribonuclease activity of RNase E. Conclusions The N-terminal region of the RNase E protein inhibits bacterial death induced by human Bax as well as paraquat through a unique mechanism that is distinct from RNA digestion. This study implies that the protection of bacterial death induced by Bax is associated with an anti-oxidant pathway and that a mutant RNase E has a novel function as an anti-oxidant. [source]

Identification and characterization of Japanese encephalitis virus envelope protein gene from swine

LETTERS IN APPLIED MICROBIOLOGY, Issue 1 2010
J.-M. Fan
Abstract Aims:, Identification and characterization of Japanese encephalitis virus (JEV) envelope protein gene from swine. Methods and Results:, Genomic RNA was separated from JEV isolated strain Henan-09-03, and used as templates for cDNA synthesis of E gene. The cDNA of E gene was amplified by RT-PCR and cloned into the pMD19-T-Vector and confirmed by sequencing. The cloned gene was then subcloned into the pET-32a and was introduced into Escherichia coli BL21 (DE3) for expression. The E protein was purified by Ni chelating column-based affinity chromatography. The molecular weight of expressed protein was about 50 kDa. Compared with the published sequence of SA14 (AF495589), the homology of the nucleotide sequence was 98% and the seven mutations resulting in amino acid substitutions at Leu 36 Ser, Leu107 Val, Ala167 Thr, Asn 230 Ser, Leu 340 Pro, Asn 430 Ile, Phe 448 Leu. Phylogenetic analysis of the E sequence of isolated strain classified it within genotype III of the JEV. The result of Western blotting indicated that the antigenicity of the protein was specific. Conclusions:, The stable expression of the protein and the analysis of its antigenic specificity provide the foundation for developing the ELISA early stage diagnosis kit. Significance and Impact of the Study:, As coating antigen, the recombinant E protein served a good source in the indirect ELISA method for the detection of JEV antibody. [source]

NMR solution structure and backbone dynamics of domain III of the E protein of tick-borne Langat flavivirus suggests a potential site for molecular recognition

PROTEIN SCIENCE, Issue 6 2006
Munia Mukherjee
Abstract Flaviviruses cause many human diseases, including dengue fever, yellow fever, West Nile viral encephalitis, and hemorrhagic fevers, and are transmitted to their vertebrate hosts by infected mosquitoes and ticks. Domain III of the envelope protein (E-D3) is considered to be the primary viral determinant involved in the virus,host-cell receptor interaction, and thus represents an excellent target for antiviral drug development. Langat (LGT) virus is a naturally attenuated BSL-2 TBE virus and is a model for the pathogenic BSL-3 and BSL-4 viruses in the serogroup. We have determined the solution structure of LGT-E-D3 using heteronuclear NMR spectroscopy. The backbone dynamics of LGT-E-D3 have been investigated using 15N relaxation measurements. A detailed analysis of the solution structure and dynamics of LGT-E-D3 suggests potential residues that could form a surface for molecular recognition, and thereby represent a target site for antiviral therapeutics design. [source]

SERCA activity is required for timely progression through G1/S

CELL PROLIFERATION, Issue 1 2001
V. R. Simon
Changes in intracellular Ca2+ correlate with specific events in the cell cycle. Here we investigated the role of Ca2+ in the G1 phase. HEK 293 cells were arrested in mitosis and subjected to short-term treatments that alter Ca2+ homeostasis prior to their release into G1. Treatment with thapsigargin (TG), an irreversible inhibitor of the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) lengthened the G1 phase. Moreover, TG treatment also resulted in a dramatic alteration in cellular morphology and attachment and in the reduction of MAPK activity and lower levels of cyclin D1 and cyclin E proteins. Treatments with reagents that transiently increase or decrease cytosolic Ca2+ or that temporarily inactivate SERCA did not alter any of the above parameters. Cells expressing a TG-resistant form of SERCA progressed normally through the G1/S transition after TG treatment. These results suggest that long-term SERCA inactivation affects cell cycle-dependent events and compromises progression through G1/S. [source]