Animals ; Arteritis Virus, Equine ; chemistry ; genetics ; Horses ; Open Reading Frames ; Viral Nonstructural Proteins ; chemistry ; physiology ; Viral Structural Proteins ; chemistry ; physiology

BACKGROUNDNumerous studies have reported a relationship between hepatitis C virus (HCV) genotype and the response to interferon therapy. Despite high sensitivity and specificity, genotyping methods can be performed only on HCV RNA positive samples. Serotyping might be a rapid and cost effective method for determining HCV genotypes, especially in patients with previously undetectable HCV RNA. In this study, an enzyme linked immunosorbent assay (ELISA) method for HCV serotyping with the genotype specific, synthetic peptides derived from HCV nonstructural 5a (NS5A) region was developed.

METHODSBased on 45 sequences, representing HCV genotypes 1 - 6 from Genebank, we synthesised 305 overlapping 30-mer peptides within NS5A region at positions 2182 - 2343 of HCV. All peptides for antigenic reactivity were tested by enzyme immunoassay with 69 human sera with antiHCV positive representing genotype 1 - 6. Forty hepatitis C patient sera were serotyped using serotype specific, synthetic peptides and genotyped by sequencing analysis.

RESULTSThe correspondence of amino acids in HCV NS5A region with amino acids in positions 2182 - 2343 was very low among different genotype peptides. The highly conserved sequences were residues 2182 - 2211 (R1), 2272 - 2301 (R7) and 2302 - 2331 (R9): the highly variable 2212 - 2241 (R3) and 2257 - 2286 (R6). Using 305 peptides, antigenic regions were located in R3, R7 and R9. Eighteen peptides from highly conserved region representing genotypes 1 to 6 showed broad immunoreactivity with sera containing antibody to all HCV genotypes. Immunoreactivity of the peptides from highly variable region was stronger with similar genotype sera. Twelve unique peptides showed highly, genotype specific, reactivity with types 1 and 3 sera. Type 2 genotype specific peptides had cross reaction with type 3 serum. No type 4, 5 or 6 specific peptides were selected. The serotyping results showed high agreement with sequencing analysis.

CONCLUSIONSThe major antigenic regions in HCV NS5A region were at 2212 - 2241 (R3), 2272 - 2301 (R7) and 2302 - 2331 (R9). Eighteen peptides from highly conserved region show genotype independent, immunoreactivity, useful for antiHCV antibody test. Twelve peptides from highly variable region show genotype 1 and 3 dependent immunoreactivity, useful for determining HCV serotype, especially for patients with previously undetectable HCV RNA.

Amino Acid Sequence ; Genotype ; Hepacivirus ; classification ; genetics ; Humans ; Molecular Sequence Data ; Serotyping ; Viral Nonstructural Proteins ; chemistry ; immunology

Human astrovirus (HAstV) is one of the leading causes of actue virual diarrhea in infants. HAstV-induced epithdlial cell apoptosis plays an important role in the pathogenesis of HAstV infection. Our previous study indicated that HAstV non-structural protein nsPla C-terminal protein nsPla/4 was the major apoptosis functional protein and probably contained the main apoptosis domains. In order to screen for astrovirus encoded apoptotic protien, nsPla/4 and six turncated proteins, which possessed nsPla/4 protein different function domain ,were cloned into green fluorescent protein (GFP) vector pEG-FP-N3. After 24-72 h transfection, the fusion protein expression in BHK21 cells, was analysis by fluorescence microscope and Western blot. The results indicated seven fusion proteins were observed successfully in BHK21 cell after transfected for 24 h. Western blot analysis showed that the level of fusion protein expressed in BHK21 cells was increased significantly at 72h compared to 48h in transfected cells. The successful expression of deletion mutants of nsPla/4 protein was an important foundation to gain further insights into the function of apoptosis domains of nsPla/4 protein and it would also provide research platform to further confirm the molecule pathogenic mechanism of human astrovirus.
Amino Acid Motifs ; Astroviridae Infections ; virology ; Humans ; Mamastrovirus ; genetics ; metabolism ; Mutation ; Sequence Deletion ; Transfection ; Viral Nonstructural Proteins ; chemistry ; genetics ; metabolism

Amino Acid Sequence ; Hepatitis C, Chronic ; drug therapy ; Humans ; Interferons ; pharmacology ; therapeutic use ; Viral Nonstructural Proteins ; chemistry ; drug effects ; genetics

Faldaprevir analogue molecule (FAM) has been reported to effectively inhibit the catalytic activity of HCV NS3/4A protease, making it a potential lead compound against HCV. A series of HCV NS3/4A protease crystal structures were analyzed by bioinformatics methods, and the FAM-HCV NS3/4A protease crystal structure was chosen for this study. A 20.4 ns molecular dynamics simulation of the complex consists of HCV NS3/4A protease and FAM was conducted. The key amino acid residues for interaction and the binding driving force for the molecular recognition between the protease and FAM were identified from the hydrogen bonds and binding free energy analyses. With the driving force of hydrogen bonds and van der Waals, FAM specifically bind to the active pocket of HCV NS3/4A protease, including V130-S137, F152-D166, D77-D79 and V55, which agreed with the experimental data. The effect of R155K, D168E/V and V170T site-directed mutagenesis on FAM molecular recognition was analyzed for their effect on drug resistance, which provided the possible molecular explanation of FAM resistance. Finally, the system conformational change was explored by using free energy landscape and conformational cluster. The result showed four kinds of dominant conformation, which provides theoretical basis for subsequent design of Faldaprevir analogue inhibitors based on the structure of HCV NS3/4A protease.
Antiviral Agents ; chemistry ; Carrier Proteins ; chemistry ; Drug Resistance, Viral ; Endopeptidases ; Hepacivirus ; Molecular Dynamics Simulation ; Mutagenesis, Site-Directed ; Oligopeptides ; chemistry ; Protease Inhibitors ; chemistry ; Serine Proteases ; Thiazoles ; chemistry ; Viral Nonstructural Proteins ; chemistry

Hepatitis C virus (HCV) is a positive sense, single-stranded RNA virus in the Flaviviridae family. It causes acute hepatitis with a high propensity for chronic infection. Chronic HCV infection can progress to severe liver disease including cirrhosis and hepatocellular carcinoma. In the last decade, our basic understanding of HCV virology and life cycle has advanced greatly with the development of HCV cell culture and replication systems. Our ability to treat HCV infection has also been improved with the combined use of interferon, ribavirin and small molecule inhibitors of the virally encoded NS3/4A protease, although better therapeutic options are needed with greater antiviral efficacy and less toxicity. In this article, we review various aspects of HCV life cycle including viral attachment, entry, fusion, viral RNA translation, posttranslational processing, HCV replication, viral assembly and release. Each of these steps provides potential targets for novel antiviral therapeutics to cure HCV infection and prevent the adverse consequences of progressive liver disease.
Antigens, CD81/metabolism ; Genome, Viral ; Hepacivirus/genetics/*physiology ; Humans ; RNA, Viral/metabolism ; Scavenger Receptors, Class B/metabolism ; Viral Envelope Proteins/chemistry/metabolism ; Viral Nonstructural Proteins/chemistry/metabolism ; Virus Assembly ; Virus Internalization ; Virus Replication

Dengue virus (DENV) is a re-emerging disease transmitted by the Aedes mosquitoes and has become a major public health problem in southern China. Currently, no antiviral drug or effective vaccine exist to control this disease. The chimeric DENV structural protein vaccine cannot elicit balanced levels of protective immunity to each of the four viral serotypes; therefore, non-structural protein components may be required to construct an effective DENV vaccine. The Dengue virus non-structural 1 (DENV NS1) protein plays a critical role in viral pathogenesis and protective immunity. Therefore, immunity to Dengue 1-4 NS1 subtypes may be crucial for the prevention of severe disease. This review attempts to provide an overview about the structure and function of DENV NS1.
Animals ; Dengue ; immunology ; prevention & control ; virology ; Dengue Vaccines ; chemistry ; genetics ; immunology ; Dengue Virus ; chemistry ; genetics ; immunology ; Humans ; Viral Nonstructural Proteins ; chemistry ; genetics ; immunology

Two Rotavirus G9P[8] strains (LL52696 and LL52727) were recognized during a sentinel-based survey in Lulong, China. Phylogenetic analysis of the VP7 gene showed that both strains isolated constituted a divergent genetic cluster distinct from the other G9 strains isolated in China. Analysis of VP4, VP6, and NSP4 genes revealed that these strains were closely related to Lulong strains. We hold that two strains were reassortant between G9 and Lulong predominant strains.
Amino Acid Sequence ; Antigens, Viral ; chemistry ; genetics ; Base Sequence ; Capsid Proteins ; chemistry ; genetics ; Glycoproteins ; chemistry ; genetics ; Humans ; Phylogeny ; Rotavirus ; classification ; genetics ; Toxins, Biological ; chemistry ; genetics ; Viral Nonstructural Proteins ; chemistry ; genetics

The nucleotide sequence of the VP1 (1D) and partial 3D polymerase (3Dpol) coding regions of the foot and mouth disease virus (FMDV) vaccine strain A/Iran87, a highly passaged isolate (~150 passages), was determined and aligned with previously published FMDV serotype A sequences. Overall analysis of the amino acid substitutions revealed that the partial 3Dpol coding region contained four amino acid alterations. Amino acid sequence comparison of the VP1 coding region of the field isolates revealed deletions in the highly passaged Iranian isolate (A/Iran87). The prominent G-H loop of the FMDV VP1 protein contains the conserved arginine-glycine-aspartic acid (RGD) tripeptide, which is a well-known ligand for a specific cell surface integrin. Despite losing the RGD sequence of the VP1 protein and an Asp26-->Glu substitution in a beta sheet located within a small groove of the 3Dpol protein, the virus grew in BHK 21 suspension cell cultures. Since this strain has been used as a vaccine strain, it may be inferred that the RGD deletion has no critical role in virus attachment to the cell during the initiation of infection. It is probable that this FMDV subtype can utilize other pathways for cell attachment.
Amino Acid Sequence ; Amino Acid Substitution ; Antigens, Viral/chemistry/*genetics/metabolism ; Capsid Proteins/chemistry/*genetics/metabolism ; Cloning, Molecular ; Foot-and-Mouth Disease Virus/classification/*genetics/*metabolism ; Gene Expression Regulation, Viral ; Molecular Sequence Data ; Phylogeny ; Viral Nonstructural Proteins/chemistry/*genetics/metabolism

OBJECTIVETo screen HCV NS5 mimotopes by using monoclonal antibody and phage peptide library.

METHODSBy using HCV NS5 monoclonal antibody as selective molecule, a 7 peptide phage library was biopanned and positive clones were selected by ELISA, competition assay and DNA sequencing.

RESULTSTwelve positive clones were chosen for DNA sequencing. From the experiment and sequencing comparison results, one epitope was confirmed as the mimotope of HCV NS5.

CONCLUSIONSHCV mimotope is obtained by phage peptide library screening. The result provides a new approach for HCV therapy and vaccine development.

Amino Acid Sequence ; Antibodies, Monoclonal ; immunology ; Enzyme-Linked Immunosorbent Assay ; Epitope Mapping ; Hepatitis C ; therapy ; Peptide Library ; Viral Nonstructural Proteins ; chemistry ; genetics ; immunology ; Viral Vaccines ; immunology