Abstract:Carboxy-terminal amidation is an essential posttranslational modification for numerous neuronal and endocrine peptides.It is catalyzed by peptide α-amidating monooxygenase (PAM),in a two-step reaction. Peptidylglycine α-hydroxylating monooxygenase(PHM) and peptidyl-hydroxyglycine -α-amidating lyase(PAL) act in one of the two step.PHM catalytic core is composed of two nine-stranded β-sandwich domains similar in three-dimessional structure.Each domain contains an activity center with a copper coordinated by three conserved His or two His and a Met residues.In the reaction cycle of producing peptidyl α-hydroxyglycine,the two coppers are reduced independently by ascorbate,and they transfer one electron each to molecular oxygen.

Abstract:Synaptic plasticity is involved in the process of memory formation. It's proved that neural cell adhesion molecules play an important role both in promoting synaptic plasticity and keeping the synaptic stability. Many evidences have been showed that neural cell adhesion molecules can regulate some process in association with learning and memory.

Abstract:Rx (retinal homeobox) is a new gene family, which is closely correlated to the development of visual system. The expression of these genes is related to the development of eye primordia, optic vesicle, retina, forebrain and some regions of middle brain. The research of Rx genes will throw light on the regulation mechanism of development of visual system.

Abstract:Proteome research techniques are the important tools in the Post-Genome Era. A review is given about the progress in proteome research of bacteria, Haemophilus influenzae, Saccharomyces cerevisiae, C.elegans, Drosophila melanogaster and human diseases.

Abstract:Osteogenic protein-1(OP-1, or bone morphogenetic protein-7) is a member of the transforming growth factor(TGF)-β superfamily. It has been testified that recombinant human OP-1(hOP-1) indicated potent bone-inductive efficiency in vitro and in vivo. The satisfactory results were obtained from healing bone defects in many kinds of experimental animals with hOP-1.Recombinant hOP-1 has prospective clinical application.

Abstract:Calmodulin, a Ca²⁺ receptor, is an important constituent of cellular signal transduction systems. In recent years, much progress has been made on the three-dimensional structure of calmodulin, this leads the scientists to understand the mechanisms of the activation of calmodulin by Ca²⁺ and the interaction between calmodulin and its target enzymes. A concise description is given on the 3D structures of Apo-calmodulin, Ca²⁺-calmodulin and the complex of calmodulin with its target peptides and antagonists.

Abstract:The gene zif268 codes for a transcription factor ZIF268. The expression pattern of zif268 in developing visual cortex is regulated. zif268 is highly expressed in adult visual cortex which experienced normal visual input. After visual deprivation, the expression level of zif268 is strongly down-regulated, while visual stimulation can significantly increase the expression level of zif268. The studies concerning the expression pattern of zif268 offer further insight into the physiological functions of zif268 in the mammalian visual system.

Abstract:The regulation of apoptosis is an essential mechanism for physiological cell death and tumorigenesis. The analysis of the genetic machanisms reponsible for susceptibility to or protection from apoptosis stimuli not only enables us to gaininsight into tumor cell biology,but may also prove useful in the development of new therapeutic strategies. Among the proteins coded by the genes of BCL2 family,BCL2,BCL-X_L,MCL-1,CED-9,BAG-1,E1B-194 and A1 act as death repressors, whereas BAX, BAk, BCL-X_s and BAD promote cell death. These different functions were shown to be mediated by homodimerzation/heterodimerization of the various family members. Therefore a critical balance between molecules above may determine the fate of cells in reponse to apoptosis-inducing conditions.

Abstract:Protein C-terminal sequence analysis is an important technique in protein chemistry and molecular biology. (iso)Thiocyanate approach appears to be the prevailing method since it was first described by Schlack and Kumpf in 1926. The chemical mechanism, the advances of (iso)thiocyanate approach and the preparation of amino acid thiohydantoins are reviewed and discussed in detail.

Abstract:Extra cellular matrix (ECM) is a dynamic reticular structure, which distributes among cell spaces. The structural proteins of ECM are varied and include collagens, proteoglycans, multidomain glycoproteins and other biomacromolecules. These proteins can combine with the specific receptors which exist on the surface of cells. This will result in different gene expression by connecting with intracellular skeleton frame directly or initiating signal transduction cascades, and lead to cells proliferation and differentiation. Matrix Metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play an important role in the process of ECM destruction and remodeling. MMPs is also a Zn²⁺ dependant proteolytic enzyme. MMPs expression is regulated strictly by growth factors, cytokines, and hormones at transcription level, by their natural activators and inhibitors at protein level. MMP participate various cells physiological and pathological process by degrading different ECM components.

Abstract:Advances in new label strategies and application of liquid crystalline medium for giving additional structural information have improved the accuracy of solution protein structures determined by NMR, and extended the molecular weight limit. Several structures of proteins of 30 ku have been solved using ¹⁵N,¹³C,²H labeling multidimensional NMR techniques, and this limit will probably be surpassed in the near future.

Abstract:The recent advance in structure-function studies of cellulases by structural biology and protein engineering is reviewed.The seperation of structural domains and the structure-function studies of catalytic domains and cellulose-binding domains are included.The research prospects of cellulases are forecasted.According to the sequence similarity of amino acid, cellulase and hemicellulase can be divided in to nine families, and in five families there are some enzymes that three dimension structure have been resolved.Here, three dimension structure of some cellulase and xylanase were compared, and the relationship between its molecular folding and catalytic mechanism were also analyzed.

Abstract:Accumulated evidence suggests that salicylic acid is an important endogenous signal molecule in the activation of several plant defense responses. The function of salicylic acid involved in plant disease resistance is introduced, and the molecular mechanisms of salicylic acid inducing plant disease resistance have been established at the interaction of salicylic acid with hydrogen peroxide and its metabolizing enzymes. Finally, some important aspects for further studying are suggested.

Abstract:Insect baculovirus-encoded ecdysteroid UDP-glucosyltransferase (EGT) are not essential enzymes which catalyze the conjugation of ecdysteroids with UDP-glucose. In vivo, the sugar conjugation of ecdysteroids by EGT causes suppression of host molting. The deletion of egt gene actually improves the pesticidal properties of the baculovirus. Insects infected by an egt-minus virus display reduce feeding and earlier death than those infected by wild-type virus. The recent advances in the studies of the egt gene and protein, EGT-catalyzed conjugation, EGT effects on host development and suvival as well as biological role of EGT are introduced.

Abstract:Heme oxygenase (HO) isoforms in hematin and phenylhydrazine-induced Sprague-Dawley rat liver and brain were purified using DEAE-Sephacel and hydroxylapatite. Rat liver HO-1 and brain HO-2 were determined by the Western blotting analysis. The results showed that two isoforms were purified and identified from the induced rat liver, and the HO-1 was the predominant form with a ratio of 2∶1. In the native state, the activity of HO-2 was detected to be fully refractory to hematin and phenylhydrazine, whereas the activity of HO-1 was increased in response to these agents. The apparent molecular weights of HO-1 and HO-2 were about 30 ku and 36 ku respectively. In the untreated liver and treated brain, only one peak of HO activity (HO-2) was detected. The antiserum against liver HO-2 was employed in Western blotting analysis, cross-reactivity of HO-2 in the brain was observed, and that of HO-1 in the liver was not observed. The study suggests that HO-1 and HO-2 exist in the hematin and phenylhydrazine treated rat liver, HO-1 is an inducible enzyme, and only HO-2 exists in the treated rat brain. Two constitutive forms were different in molecular weight, inducibility and immunochemical properties.

Abstract:Microscopic quasi-elastic laser light scattering technique and image processing and analysis technology were used to study thalassemia erythrocytes. The mean hydrodynamic radius and average diffusion coefficient of hemoglobin polymers in the intact red cells, the membrane motion frequency, cross area,regular form factor,longest axis,shortest axis and mean gray were measured for thalassemia erythrocytes and normal red cells. It is found that, compared with normal red cells, the mean hydrodynamic radius and its variance of thalassemia erythrocytes are larger, the membrane motion frequency is slower and the cross area of the cell is smaller. This suggests that thalassemia erythrocytes have large hemoglobin polymers and worse deformability.

Abstract:Radioligand binding assay and competitive radio-assay of ¹²⁵I-EGF on plasma membrance EGF receptor and radio-receptor assay when ¹²⁵I-EGF was incubated with human glioblastoma multiforme cells were carried out. The results showed that there is a high affinity binding site on BT325 cells plasma membrance, exogenous GM3 could not alter the affinity (K_d) of EGF binding with cell-surface receptors, but decrease the receptor number. GM3 could significantly prolong the endocytosis process of EGF-EGFR complex. The concentration of EGF in culture medium was unchanged by GM3 and BBG,but that of EGF in cytoplasm was increased by GM3. It suggested that GM3 might inhibit the secretion of EGF.

Abstract:Using flow cytometry(FCM) to measure IgG binding to red blood cells(RBC) exposed to H₂O₂ and their autofluorescence directly, in order to study the effect of H₂O₂ on the antigenicity and the production of fluorescent product of LPO of RBC. The results showed that the changes of both antigenicity and autofluorescence were dependent on the H₂O₂ concentration and the time of RBCs exposed to H₂O₂, and the change of antiginicity was more susceptible to H₂O₂ than that of autofluorescence. At 10² fold lower H₂O₂ concentration than that made autofluorescence significantly increase, IgG bond to RBC. Furthermore, it was found that the changes of antigenicity and autofluorescence were related to forward scatter (FSC).

Abstract:Transesterification of non-natural trimethylsilyl alcohol with fatty ester in organic phase could be catalyzed by lipase from Candida cylindracea. The transesterification reaction was apparently affected by the hydrophobicity of reaction medium, the water activity of the reaction system and the structure of the substrates. n-Octane was found to be the best medium for the reaction and the optimum water activity for the reaction is about 0.55.

Abstract:Human G-CSF genomic DNA was obtained by PCR and mammary expression vector was constructed using WAP gene 2.6 kb promoter as control element. Two transgenic mice were produced by microinjection method and identified by PCR and Southern blot. G-CSF expression level was as low as 120～250 μg/L in transgenic mice milk. In order to study the cause of its low expression, human G-CSF gene was amplificated by RT-PCR in mammary gland of mice. Sequence analysis showed that this gene missed the fourth exon that was recoginsed as the intron due to RNA abnormal splice. It is possible that RNA abnormal splice lead to low expression in transgenic mice.

Abstract:It was expected that there are a coil (289～325) and two α helix (α₁ 368～373,α₂ 381～388) structures in p53 protein C-terminal region based on its mRNA secondary structure template and Chou-Fasman's protein secondary structure principle of prediction. The result was conformed by the other four methods of protein secondary structure prediction that are based on the multiple sequence alignment (accuracy=73.20%). Combine with the 31 amino acids crystal structure of the oligomerization, the three dimensional conformation of p53 C-terminal 108 residues was built using the SGI INDIGO² computer. This structure further expounds the relationship among those biological function domains of p53 C-terminus at three-dimensional level.

Abstract:Combined protein homologous modeling with analysis of electrostatic surface potential energy, mutant ricin toxin A chain, which was suggested to be bioactive, was designed. The gene of ricin toxin A chain was amplified by PCR and inserted in pKK223-3 to construct a prokaryotic expression vector, which was highly expressed in E.coli system. Moreover, the expression products showed obvious cytotoxicity, just in agreement with the prediction of modeling.

Abstract:Based on the reaction that 2,3-diaminonaphthalene(DAN) has the ability trapping ^·NO to yield the highly fluorescent 2,3-naphthotriazole, a new fluorometric method has been reported, which combines the nitrogen gas purging system and fluorescent analysis together. The results indicated that the fluorescence intensity of the measuring solution is ^·NO concentration and acidified nitrite concentration dependent. Five acidified samples of normal human plasma have been determined and the released ^·NO is about (31.04±4.70) nmol/L. Since this method separates the sample from the measuring solution, it can avoid the interference from the sample to the fluorescence analysis so that it can be used to measure biological sample and continuously observe the ^·NO releasing.

Abstract:In order to study the molecular pathology of hereditary persistence of fetal hemoglobin (HPFH) in Chinese, PCR-based chemical cleavage of mismatch (CCM) method was used for defining the point mutations causing non-deletional HPFH. 415 bp ^Gγ- and ^Aγ- globin gene promoter regions of 4 previously identified mutants were amplified by nested PCR, then the mutations were detected by CCM, and the optimal condition was determined. It was proved that CCM is a simple and reliable molecular diagnostic method for the detection of nd HPFH point mutations.

Abstract:Although hydrogen peroxide is generated in cells by normal metabolism, the reaction of the stress or by treatment of the cells with 0.4 mmol/L of hydrogen peroxide for 8～24 hours can result in DNA damage. 8-hydroxyguanine is a typical hydroxyl radical-induced products in DNA.The yields of the 8-hydroxyguanine in DNA isolated from H₂O₂-treated HL-60 cells in different ways were reported.The 8-hydroxyguanine in the cells treated in more than 0.4 mmol/L H₂O₂ for eight hours.In order to identify the 8-hydroxyguanine, the result was confirmed by CGC/MS-SIM. The results suggested that the nuclear DNA damage in cells caused by H₂O₂ may be involved in formation of hydroxyl radicals.

Abstract:To investigate the function，function regulation and structure-function relationship of endothelial nitric oxide synthase(eNOS)，a gene fragment encoding eNOS 801～902 AA residues was cloned by PCR, and inserted into pET-28a(+) expressive vector. The resulted pET-28a/eNOS₂ was transformed into BL₂₁ host E.coli and expressed by IPTG induction for 4 hour, The expressed protein (14.4 ku) was purified by His-Bind^TM Sephorose colum and SDS-PAGE, thus providing the basis for the selection of the eNOS-specific inhibiting peptides and the preparation of the specific antibody against eNOS.

Abstract:Androgen Insensitivity syndrome (AIS) is a X-linked recessive disease mainly associated with the defect of androgen receptor(AR). A method was established by which the AR gene can be amplified by PCR directly from the dried blood spot or from the wash-fluid of dried blood spot. The PCR products from dried blood spot have good specificity. Combining this method with SSCP and direct DNA cycle sequencing，the point mutations and the fragment changes of AR gene can be identified.This method is simple, economical and it offers the possibility of mutation analysis of AR gene or other genes from patients who live in remote countryside.

Abstract:The transfection of Cos-7, Vero and Namalwa cell lines by lipofection and electroporation methods have been examined. The lipofection method was found to be better than electroporation method in terms of higher transfection and convenient use. The electroporation method is superior to the lipofection method in terms of average transfection efficiency for a wider variety of cells lines. It was found that Namalwa cells could only be transfected by electroporation method, while Cos-7 and Vero cells could be transfected by both methods.

Abstract:Matrix metalloproteinase-2 (MMP-2) plays important role in tumor invasion and metastasis. MMP-2 is expressed in yeast expression system for further studying its function mechanism. The expression sequence of MMP-2(gelatinase A) have been obtained by PCR amplifying,restriction enzyme cut and sequencing analysis demostrate that the sequence is correct. The expression vector pPIC9/GelA containing gelatinase A sequence is constructed and transformed the yeast Pichia pastoris. The gelatin enzymography demostrate that recombinant protein secreted by transformant yeast is capable of degrading gelatin and the molecular weight of the matrix metalloproteinase-2 is 66 ku in SDS-PAGE.

Abstract:Some important bioinformatical web sites and searching engines were introduced, in order to make good use of biological resource on line.

Abstract:Temperature gradient gel electrophoresis (TGGE) is a new and powerful electrophoresis method for separation of nucleic acids (DNA and RNA) and analysis of sequence variations. The TGGE method uses the melting temperature(T_m) as an important parameter to identify DNA, which differs in sequence among a mixture of molecules of the same size but different conformation. With the advantages of high-resolution capability, high reproducibility and timesaving process, the TGGE technique has been applied broadly in the field of molecular biology.