Fluorescence resonance energy transfer(FRET)is increasingly used to study inter-and intramolecular interactions in living cells.Since being proportional to the concentration of the donor-acceptor complex.FRET value must be normalized to exclude the influence of the ratio and the concentration of donor and acceptor for comparison.Different from the intra.molecular FRET which is simplified by the fact that the COncentration of the donor is equal to that of the acceptor,the inter-molecular FRET is usually too complicated for most existing measurements to quantify exactly.We deduced the exact proportion of the donor-acceptor complex based on a unique characteristic of homodimer,a special kind of the intermolecular interaction,developed an exact quantification measurement of the FRET.We proved the novel method Can generate more reliable estimation of FRET value by comparison with other methods using a homodimer,estrogen receptor alpha(ERa),as a FRET pair.

To better understand the cleavage efficiency of muhiribozyme system on its RNA substrate in the presence and absence of divalent magnesium and monovalent sodium ions.we constructed pGEM-Coat'A,pGEM-Coat'A196Rz plasmids and pGEM-MDRl target plasmid.They were applied to transcribe RNAs with SP6/T7 transcription kit.Cleavage reactions were carried out in cell-free system and reaction products were analyzed by electrophoresis on 6% denaturing polyacrylamide gels in TBS buffer.The gels were dried and exposed to X-ray films for autoradiography.The Image J software was employed to analyze the dried gels.The results indicated that the cleavage efficiency of the muhiribozyme was dependent on the concentration of divalent Mg2+.The cleavage products increased with the concentrations of divalent Mg2+ and were Mg2+ concentration and time dependent.No cleavage product was obtained in the presence of lower than 200 mmol/L Na+ alone.On the contrary,monovalent Na+ inhibited the Mg2+ -induced cleavage reaction in Na+ and Mg2+ coexistance.The cleavage rate was significantly lower than that observed with divalent Mg2+ alone.These results suggested that divalent Mg2+ was required for muhiribozyme on substrate cleavage reaction in the physical condition,whereas monovalent Na+ was not.

The complete mitochondrial genome sequence of Phlaeoba albonema Zheng Was determined by using L-PCR and conserved primers walking sequencing.The obtained genome sequence is 15657 bp in size.containing 13 protein-coding genes,2 ribosomal RNA and 22 transfer RNA genes.All the 37 genes are conserved in the same orientations as observed in Locusta migratoria.11202 bp of the mtDNA are coding for proteins,1486 bp for tRNAs,1312 bp for rRNA large subunit(1rRNA),and 844 bp for rRNA small subunit(srRNA).The A+T-rich region is 728 bp in size.The genes overlapping sequences are 41 bp in total and are spreading over 9 locations(1-8 bp at each site).A total of 126 bp intergenic spacer sequences are scattered in 21 regions at the size of 1 to 20 bp,where the largest 20 bp region iS located between the tRNALys and ATP8 genes.The predicted secondary structures of both srRNA and lrRNA were compared with that of Ruspolia dubia,and the patterns of base pairs in tRNA anticodon stem and A/T,C/G bias of protein-coding genes in different strands were discussed.

Many proteins from mushrooms can be used as potential antiviral agents and in plant protection.An antiviral protein,designated as y3,Was isolated from fruiting bodies of the fungus Coprinus comatus by fastflow ion-exchange column chromatography coupled with high-resolution molecular sieve chromatography.This glycoprotein was detected in both fruiting body and mycelium by Western blot analysis.According to its Nterminal sequence.an amino acid sequence and a partial cDNA sequence of the y3 gene were obtained.Protein y3 at 2.0μg/ml achieved 50.0% inhibition of tobacco mosaic virus(TMV,20μg/ml)lesions in Nicotiana glutinosa leaves.It also inhibited multiplication of TMV in Nicotiana tabacum Var.K326.

A subcellular proteomic method was applied to investigate the protein expression profiles of nasopharyngeal carcinoma (NPC) cell lines,CNE1 and CNE2,at various differentiation levels.Plasma membrane (PM) proteins were obtained by Percoll density grade centrifugation and subjected to twodimensional electrophoresis (2DE) followed by PDQuest software analysis.Nine proteins expressed with more than two folds difference were identified by MALDI-TOF-TOF,of which functions involved in cell differentiation,signal transduction,and metabolism.Half of these proteins,such as galectin-1 and annexin Ⅱ,were analyzed with real-time quantitative PCR or Westem blotting.We have tested a proteomic method to study differentiated NPCs at different levels and found several proteins that might be related to their biological characteristics.

Based on the characteristics of salt.alkalinized soil in northeastem China,twenty-five kinds of salt alkaline conditions with different salinities and pH were simulated by mixing NaCl,NaHCO3,Na2SO4,and Na2CO3,in various proportions and applied to sunflower (Helianthus annuus L.) seedlings to investigate the coordinative effects of salt and alkali stresses on its antioxidant enzyme system.The soil was conditioned with a salt concentration range between 50 to 250 mmol/L and pH values from 7.12 to 10.46.Several physiological indexes of stressed seedlings were measured,including the activities of superoxide dismutase (SOD),catalase (CAT),and pemxidase (POD),as well as the content of malondialdehyde (MDA).The results showed that the responses of the antioxidant enzyme system in sunflowers were influenced by salinity and alkalinity,which all three antioxidant enzymes exhibited a rise-drop pattern as salinity increased,whereas their responses to alkalinity appeared to be diverse:decreased for SOD and CAT,and increase for POD along when increasing alkalinity.A two-way analysis of variance (ANOVA) showed that the effects of salinity and alkalinity on the activities of the three enzymes were significant (P＜0.001).The effect of salinity on POD and SOD was greater than that of alkalinity,whereas the effect of alkalinity on CAT was greater than that of salinity.The interrelation of salinity and alkalinity on each antioxidant enzyme was significant (P＜0.001) except for SOD.The correlation and stepwise regression analyses between the activity of the antioxidant enzyme system and the MDA content were significant to difierent extend,SOD was a dominant factor,and POD was neglectable.

The effects of melittin on the activities of Na+-K+-ATPase and glucose-6-phosphate dehydrogenase (G-6-PD) which are on the membrane of red blood cell (RBC) are chosen as the index of this study. The possible target sites of these effects through enzyme activity determination by spectrophotometry are investigated, and the hemolytic process and the activity change of these two types of enzymes on the RBC membrane are discussed. The results show that the main mode of melittin inhibition to the activity of enzymes on the RBC membrane is the coexistence of adhesion/insertion form and free-state form, and the effect of the former is more stronger than the latter. The K+ binding site of Na+-K+-ATPase is one of the target sites of melittin. The membrane-insertion process of melittin synchronizes with the action of melittin on this enzyme. Melittin slowly inhibits the catalysis of G-6-PD through the action on G-6-P and NADP, and the extent in which melittin forms tetramers isclosely related to the enzyme activity. EDTA inhibits the aggregation of melittin, and interferes with its action on G-6-P. The biochemical mechanisms of melittin effects on the substrate G-6-P and the coenzyme NADP are similar, and the inhibition of melittin is not related to the structure of G-6-PD.

The enzymatic synthesis of endomorphins were carried out by immobilized papain on sodium alginate-chitosan (IPSAC). The reaction has been carried out in two steps. First, Trp-Phe-NH2 was obtained by Boc-Trp-OH coupling with Phe-NH2 using IPSAC catalyst in microaqueous acetonitrile system with a 27.8 % yielding as determined by high performance liquid chromatography (HPLC). The catalytic properties of IPSAC were examined by studying the dependence of pH, ionic strength, solution content, reaction temperature,enzyme loading and reaction time over the yields. The results of orthogonal experiments indicated that pH was the most significant factor that influenced this synthesis. Second, Boc-Tyr-Pro-OMe and Trp-Phe-NH2 were suspended into the microaqueous acetonitrile to produce Tyr-Pro-Trp-Phe-NH2 (endomorphin-1) with a 35.2% yield.

Proteomic analysis of core needle biopsy (CNB) sample from patient populations is critical to our understanding of human disease,but has been hindered by its particular small size.Here,we present a method for the proteomic analysis of CNB sample based on the two dimensional electrophoresis.Proteins were extracted directly from 3 rat liver CNB specimens and a human prostate CNB sample.respectively.24 cm Immobiline DryStrip (pH 3-10NL) and 12.5% SDS-PAGE were introduced to separate the proteins.Interesting spots were analyzed by MALDI TOF/TOF mass spectrometry after tryptic digestion.With this method,consistent electrophoretic patterns of more than 2 500 protein spots were reproducibly obtained after silver staining,from rat liver CNB specimens.Qualitatively and quantitatively reproducible results also yield when the method was applied to a human prostate CNB sample.57 stochastically selected protein spots were analyzed by MALDI TOF/TOF moss spectrometry.and were identified with high confidence including faint ones.This simple and reproducible approach raises the opportunity of defining key molecular events of human disease pathologies.

B cell maturation antigen (BCMA) is a receptor of B lymphocyte stimulator (BLyS). Human IgG1Fc fusion proteins with the extracellular domain of BCMA(eBCMA), also called decoy receptors, have beenused as a potential BLyS antagonists to block BLyS activities. In order to design novel BLyS antagonistpeptides, computer-aided homologue modeling was used to construct an eBCMA-Fc fusion protein based on thecrystal structures of BCMA and Fc fragmant. To ensure the activity of eBCMA not to be interfered by Fcfusion, the root mean square distance (RMSD) for eBCMA and Fc were calculated to be 0.036 nm and 0.064nm, respectively, based on molecular docking modeling. An eBCMA-Fc fusion gene was constructed andintroduced into E. coli for expression. As expected, the purified 36 kD eBCMA-Fc fusion protein was able tobind BLyS in vitro at a dosage-dependent manner and demonstrated an anti-proliferative activity induced byBLyS in Daudi cells. The results have provided useful information on the evaluation of computer modeling andthe in vitro biological activity for the design of potential BLyS antagonist peptides.