检索结果-南通市图书馆

Chinese Journal of Chemistry 2002年第5期20卷 467-473页

作者：宋浩威岳贵花陆宇杨芃原王洪海 Department of Chemistry Fudan University Shanghai 200433 China State Key Laboratory of Genetic Engineering Fudan University Shanghai 200433 China

A novel approach of sequence pattern correlation has been applied to predict an expected amino acid sequence from CID ESI MS spectra. The proposed approach deduces sequence patterns with no help from known protein database such that it is useful to identify an unknown peptide or new protein. The algorithm applies a cross correlation to match an experimental CID spectrum with predicted sequence pattern generated from fragmentation information. The fragmentation knowledge of both y series and other non y series are utilized to generate the predicted sequence patterns. In contrast to the normal de novo approach, the proposed approach is insensitive to mass tolerance and non susceptive to spectral integrality with no need for selection of a starting point.

关键词： mass spectrometry sequence pattern correlation amino acid sequence protein and peptide

维普期刊数据库

Locking Function of a Key Residue in Kinesin＇s Gating Mechanism

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2014年第4期31卷 201-205页

作者： GENG Yi-Zhao ZHANG Hui JI Qing YAN Shi-Wei College of Nuclear Science and Technology Beijing Normal University Beijing 100875 School of Science Hebei University of Technology Tianjin 300401 Institute of Biophysics Hebei University of Technology Tianjin 300401

In kinesin＇s mechanochemical cycle, ATP＇s binding to the nucleotide-free leading head is exquisitely gated so that futile hydrolysis is effectively avoided, Experiments show that, when both kinesin heads bind to a microtubule~ ATP cannot bind to kinesin＇s leading head when the neck linker （NL） of this head has a backward orientation. How NL＇s backward orientation is maintained needs understanding on a structural basis. By using steered molecular dynamics and rrmtation simulations, we investigate the backward-pointing conformation of the leading head＇s NL under different inter-head tensions. We find that the NL cannot keep in a strict backward orientation solely by the inter-head tension. LYS325 （amino acid sequence in 2KIN） has an assistant locking function which locks the NL and β0 to the β-domain. This locking function has an enhanced positive cooperation with the inter-head tension. When the inter-head tension is weakened, this locking function can be broken, resulting in a loose backward orientation of the NL. The difference between the strict and loose backward orientation of the NL might be a crucial factor in the gating mechanism. These results are consistent with relevant experiments and proposals.

关键词： KINESIN MICROTUBULES HYDROLYSIS NUCLEOTIDES -- Spectra CONFORMATIONAL analysis amino acid sequence

Nonlinear Dynamics Approach to the Correlation Analysis of Protein sequences

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2002年第3期19卷 434-436页

作者：黄延昭肖奕 DepartmentofPhysics HuazhongUniversityofScienceandTechnologyWuhan430074

To clarify the randomness of protein sequences, we make a detailed analysis of a set of typical protein sequences representing each fold by usingthe nonlinear prediction method developed in nonlinear dynamics theory. No deterministic structures are found in these protein sequences and thisimplies that they behave as random chains. We also explain the controversial results obtained in previous investigations.

关键词： amino acid sequence sequences Nonlinear Dynamics Random Number Generators Protein Correlation analysis Prediction methods

Detection of anti-preS1 antibodies for recovery of hepatitis B patients by immunoassay

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2002年第2期8卷 276-281页

作者： Jun Wei Guang-Di Li Yuan Wang Zu-Chuan Zhang,Institute of Biochemsitry and Cell Biology,Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,Shanghai 200031,China Yu-Qin Wang Zhi-Meng Lu,Department of Clinical virology,Rui-Jin Hospital,Shanghai Second Medical University 200025,Shanghai,China Institute of Biochemsitry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai 200031 China.

AIM: To establish a convenient immunoassay method based on recombinant antigen preS1(21-119aa) to detect anti-preS1 antibodies and evaluate the clinical significance of antibodies in hepatitis B. METHODS: The expression plasmid pET-28a-preS1 was constructed, and a large quantity of preS1(21-119aa) fragment of the large HBsAg protein was obtained. The preS1 fragment purified by Ni(2+)-IDA affinity chromatography was used as coated antigen to establish the indirect ELISA based on streptavidin-biotin system for detection of the anti-preS1 antibodies in sera from HBV-infected patients. For follow-up study, serial sera were collected during the clinical course of 21 HBV-infected patients and anti-preS1 antibodies, preS1 antigen, HBV-DNA and other serological HBV markers were analyzed. RESULTS: preS1(21-119aa) fragment was highly expressed from the plasmid pET-28a-preS1 in a soluble form in *** (30mg.L(-1)), and easily purified to high purity over 90% by one step of Ni(2+)-IDA-sepharose 6B affinity chromatography. The purity and antigenicity of the purified preS1(21-119aa) protein was determined by 150g.L(-1) SDS-PAGE, Western blot and a direct ELISA. Recombinant preS1(21-119aa) protein was successfully applied in the immunoassay which could sensitively detect the anti-preS1 antibodies in serum specimens of acute or chronic hepatitis B patients. Results showed that more than half of 19 acute hepatitis B patients produced anti-preS1 antibodies during recovery of the disease, however, the response was only found in a few of chronic patients. In the clinical follow-up study of 11 patients with anti-preS1 positive serological profile, HBsAg and HBV-DNA clearance occurred in 6 of 10 acute hepatitis B patients in 5-6 months, and seroconversion of HBeAg and disappearance of HBV-DNA occurred in 1 chronic patients treated with lavumidine, a antiviral agent. CONCLUSION: The high-purity preS1(21-119aa) coated antigen was successfully prepared by gene expression and affinity chrom

关键词： amino acid sequence Antibodies Base sequence Genetic Vectors Hepatitis B Hepatitis B Surface Antigens Humans Immunoassay Molecular sequence Data Peptide Fragments Protein Precursors Recombinant Fusion Proteins Research Support, Non-U.S. Gov't Viral Envelope Proteins

Purification,Characterization and ~1H NMR Resonance Assignment of an α-Like Neurotoxin BmK 16 from the Venom of Chinese Scorpion Buthus martensii Karsch

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2003年第10期21卷 1378-1384页

作者：张乃霞吴宫王中华吴厚铭 State Key Laboratory of Bioorganic and Natural Products Chemistry

A natural scorpion toxin BmK 16 was purified for the first time from the venom of the Chinese scorpion Buthus martensii Karsch (BmK) by using combined gel filtration, ion exchange and reversed phase chromatography. The sequence of the N terminal 8 amino acid residues was determined by Edman degradation. Using the N terminal sequence as a tag, the database searching revealed a hit in the scorpion cDNA Bank. The sequence for N terminal 8 amino acid residues, molecular weight and amino acid compositions of BmK 16 were identical with the calculated values according to the first 64 residues' sequence of the precursor peptide alpha neurotoxin TX16 derived from the sequence of the cDNA AF156597 (EMBL). The sequence specific resonance assignment of BmK 16 was achieved and the intact sequence of BmK 16 was determined as followings: VRDAY IAKPH NCVYE CARNE YCNDL CTKNG AKSGY CQWVG KYGNG CWCKE LPDNV PIRVP GKCH. Furthermore, the results from the sequence homology analysis and the toxicity assays indicated that BmK 16 was an α like scorpion neurotoxin.

关键词： scorpion toxin Buthus martensii Karsch BmK 16,αlike scorpion neurotoxin amino acid sequence resonance assignment

维普期刊数据库

Mutation trend of hemagglutinin of influenza A virus: a review from a computational mutation viewpoint

在线全文

学校读者我要写书评

暂无评论

Acta Pharmacologica Sinica 2006年第5期27卷 513-526页

作者： Guang WU~1 Shao-min YAN Computational Mutation Project.DreamSciTech Consulting,301.Building 12.Nanyou A-zone,Jiannan Road.Shenzhen 518054,China Computational Mutation Project DreamSciTech Consulting 301 Building 12 Nanyou A-zone Jiannan Road Shenzhen 518054 China. hongguanglishibahao@***

Since 1999 we have developed two computational mutation approaches to ana-lyze the protein primary structure whose methodology and implications were re-viewed in *** first approach is the calculation of predictable and unpredict-able portions of amino-acid pairs in a protein,and the second is the calculation ofamino-acid distribution rank in a *** approaches provide quantitativemeasures to present a protein,which we have used to study a number of proteinswith numerous mutations such as p53 *** recently,we focussed ourefforts on analyzing the proteins mutating frequently over time such as hemagglu-tinins of influenza A *** this review we summarise our findings and theirimplications for hemagglutinin mutations in combination with some newly avail-able *** approaches throw light on the true nature of genetic heterogeneityof influenza virus hemagglutinins;that is,the protein variability is highly relevantto its amino-acid *** these approaches,we can monitor newmutations from influenza virus hemagglutinins and may predict their mutations inthe future.

关键词： amino acid sequence hemagglutinins influenza A virus mutation probability

Cloning of cDNA encoding Schistosoma japonicum tropomyosin and its expression in Escherichia coli

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2002年第10期115卷 1465-1469页

作者：曹建平刘述先宋光承徐馀信中国预防医学科学院寄生虫病研究所上海200025

OBJECTIVE: To perform cloning of the gene encoding Chinese Schistosoma japonicum tropomyosin (SjcTM) and its expression in Escherichia coli. METHODS: SjcTM cDNA fragment, except for 14 amino acids at the amino terminus, was obtained by reverse transcriptase-polymerase chain reaction (RT-PCR) with total RNA extracted from adult worms of S. japonicum. The RT-PCR product was cloned into T vector and sequenced. The SjcTM cDNA, derived from the constructed TA clone pGEM-SjcTM, was then subcloned into the expressing vector pBV220. After characterization by agarose gel electrophoresis, endonucleases digestion and PCR, the resultant recombinant plasmid was used for expression under the temperature-dependent condition. RESULTS: The RT-PCR product, cloned into a T vector, was sequenced and shown to be 96.5% identical at the nuclei acid level and 98.1% identical in deduced amino acid sequence to that of S. mansoni tropomyosin. The target DNA fragment was then subcloned into a prokaryotic vector pBV220. Induced expression in E. coli DH5alpha cells resulted in a constant level of recombinant protein production. The results of SDS-PAGE and Western blot revealed that the molecular weight of non-fusion recombinant protein (rSjcTM) was approximately 32 kDa and could be recognized specifically by a polyclonal antiserum specific for native S. japonicum tropomyosin (SjcTM). CONCLUSION: The engineering of the cDNA encoding S. japonicum tropomyosin and its bacterial expression was successfully made.

关键词： amino acid sequence Animals Base sequence Cloning, Molecular DNA, Complementary Escherichia coli Molecular sequence Data Recombinant Proteins Research Support, Non-U.S. Gov't Schistosoma japonicum Tropomyosin

维普期刊数据库

Relationship between genotype and phenotype of flagellin C in Salmonella

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2001年第6期7卷 864-867页

作者： Wan-Sheng Ji~1 Jia-Lu Hu~1 Jun-Wen Qiu~1 Bo-Rong Pan~1 Dao-Rong Peng~2 Bing-Long Shi~1 Shao-Juan Zhou~1 Kai-Chun Wu~1 Dai-Ming Fan~1 1 Chinese PLA Institute of Digestive Diseases2 Department of Bacteriology,Xijing Hospital,Fourth Military Medical University,Xi’an 710032,Shaanxi Province,China Chinese PLA Institute of Digestive Diseases Xijing Hospital Fourth Military Medical University Xi'an 710032 Shaanxi Province China.

AIM: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains. METHODS: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with the corresponding sequence in other strains. Salmonella strains including two typhi strains, one paratyphoid strain, one enteritidis and one typhimurium strain were isolated from outpatients. Genome DNA was purified respectively from these clinical isolates, then the corresponding flagellin C fragment was amplified by polymerase chain reaction,and the amplification products were analyzed by agarose gel electrophoresis. RESULTS: The cloned fragment includes 582 nucleotides encoding the variable region and partial conservative region of Salmonella flagellin C in plasmid pLS408. With comparison to the corresponding sequences reported previously, there is only a little difference from other strains with the same flagellar serotype in both nucleotide and amino acid level. Specific PCR products were amplified in Salmonella strains with flagellar serotype H-1-d including S. muenchen, typhi and typhimurium, but not in S. paratyphoid C or S. enteritidis strains. CONCLUSION: In this experiment, the specificity of nucleotide sequence could be found in flagellin C central variable regions as it exists in flagellar serotypes in Salmonella. It may be helpful to developing a rapid, sensitive, accurate and PCR-based method to detect Salmonella strains with serotype H-1-d.

关键词： amino acid sequence Base sequence Flagellin Genotype Molecular sequence Data Phenotype Protein Isoforms Salmonella Species Specificity

Acute hepatitis C in a chronically HIV-infected patient:Evolution of different viral genomic regions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2003年第7期9卷 1496-1500页

作者： Diego Flichman Veronica Kott Silvia Sookoian Rodolfo Campos Catedra de Virologia Facultad de Farmacia y BioquimicaUniversidad de Buenos AiresArgentina Unidad de Higado Hospital"Dr.Cosme Argerich"Argentina

AIM: To analyze the molecular evolution of different viral genomic regions of HCV in an acute HCV infected patient chronically infected with HIV through a 42-month ***: Serum samples of a chronically HIV infected patient that seroconverted to anti HCV antibodies were sequenced, from the event of superinfection through a period of 17 months and in a late sample (42nd month). Hypervariable genomic regions of HIV (V3 loop of the gp120) and HCV (HVR-1 on the E2 glycoprotein gene) were studied. In order to analyze genomic regions involved in different biological functions and with the cellular immune response, HCV core and NS5A were also chosen to be sequenced. Amplification of the different regions was done by RT-PCR and directly sequenced. Confirmation of sequences was done on reamplified material. Nucleotide sequences of the different time points were aligned with CLUSTAL W 1.5, and the corresponding amino acid ones were ***: Hypervariable genomic regions of both viruses (HVR1 and gp120 V3 loop) presented several nonsynonymous changes but, while in the gp120 V3 loop mutations were detected in the sample obtained right after HCV superinfection and maintained throughout, they occurred following a sequential and cumulative pattern in the HVR1. In the NS5A region of HCV, two amino acid changes were detected during the follow-up period, whereas the core region presented several amino acid replacements, once the HCV chronic infection had been ***: During the HIV-HCV superinfection, each genomic region analyzed shows a different evolutionary *** of the nucleotide substitutions observed are nonsynonymous and clustered in previously described epitopes,thus suggesting an immune-driven evolutionary process.

关键词： Acute Disease Adolescent amino acid sequence Female Genome, Viral HIV HIV Envelope Protein gp120 HIV Infections Hepacivirus Hepatitis C Humans Molecular sequence Data Research Support, Non-U.S. Gov't Superinfection Viral Nonstructural Proteins Viral Proteins

Identification and characterization of a novel isoform of hepatopoietin

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2002年第2期8卷 353-356页

作者： Jun Lu Wei-Min Cai,Institute of Infectious Disease,First Affiliated Hospital,Medical SchooI,Zhejiang University,Hangzhou 310003 China Wang-Xiang Xu Yi-Qun Zhan Xiao-Lin Cui Fu-Chu He Xiao-Ming Yang,Institute of Radiation Medicine,Academy of Military Medical Sciences,Beijing 100850,China Institute of infectious Disease First Affiliated Hospital Medical School Zhejiang University Hangzhou 310003 China.

AIM: To isolate a novel isoform of human HPO (HPO-205) from human fetal liver Marathon-ready cDNA and characterize its primary biological function. METHODS: 5'-RACE (rapid amplification of cDNA 5' ends) was used to isolate a novel isoform of hHPO in this paper. The constructed pcDNA(HPO-205), pcDNA(HPO) and pcDNA eukaryotic expression vectors were respectively transfected by lipofectamine method and the stimulation of DNA synthesis was observed by (3)H-TdR incorporation assay. Proteins extracted from different cells were analyzed by Western blot. RESULTS: A novel isoform of hHPO (HPO-205) encoding a 205 amino acid ORF corresponding to a translated production of 23 kDa was isolated and distinguished from the previous HPO that lacked the N-terminal 80 amino acids. The dose-dependent stimulation of DNA synthesis of HepG2 hepatoma cells by HPO-205 demonstrated its similar biological activity with HPO in vitro. The level of MAPK (Mitogen-activated protein kinase) phosphorylation by Western blot analysis revealed that HPO-205 might have the stronger activity of stimulating hepatic cell proliferation than that of HPO. CONCLUSION: A novel isoform of hHPO (HPO-205) was isolated from hepatic-derived cells. The comparison of HPO-205 and HPO will lead to a new insight into the structure and function of hHPO, and provide the new way of thinking to deeply elucidate the biological roles of HPO/ALR.

关键词： amino acid sequence Cell Division Cell Fractionation Enzyme Activation Hepatocyte Growth Factor purification Humans Liver Mitogen-Activated Protein Kinases Molecular sequence Data Open Reading Frames Protein Isoforms sequence Alignment Tumor Cells, Cultured