Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Capsid”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,243 records · Page 69Linked to original sources
PubMed1988

In vitro assembly of the outer capsid of bovine rotavirus is calcium-dependent.

The nucleocapsid protein (VP6) and outer capsid glycoprotein (VP7) of bovine rotavirus (BRV) assemble in vitro, in 0.01 M Tris-HCl, pH 8.0, 50 mM CaCl2, into smooth particles resembling double-shelled BRV. That the two proteins interact is demonstrated by the immunoprecipitation of both by antibody directed against either VP6 or VP7. The calcium-dependence, particle morphology, and immunoreactivity in ELISA suggest that VP7 is presented authentically on the outer capsid. The implications for rotavirus morphogenesis are discussed.

Animals↗
PubMed1988

Capsid protein VP1 (p85) of Aleutian disease virus is a major DNA-binding protein.

The interaction between Aleutian disease virus (ADV) DNA and proteins isolated from ADV-infected cells or ADV virions, respectively, was examined. Proteins were separated on SDS-polyacrylamide gels, transferred to nitrocellulose, and probed with 32P-labeled restriction fragments of replicative form (RF) DNA or with single-stranded virion DNA. The ADV capsid protein VP1 was found to bind the 3'-terminal BamHI fragment of RF DNA extending from map units (m.u.) 0 to 15. No binding was observed with the fragment extending from m.u. 15 to 63 and only minor amounts of label were detected with the 5'-terminal EcoRV fragment extending from m.u. 63 to 100. With the latter fragment, small amounts of label were also detected bound to higher-molecular-weight proteins of about 100,000 Da. No binding of DNA to the ADV nonstructural protein NS1 or to the ADV capsid protein VP2 was detected. Additionally, single-stranded virion DNA was found to bind to VP1.

Aleutian Mink Disease Virus↗
PubMed1988

Protein 3CD is the major poliovirus proteinase responsible for cleavage of the P1 capsid precursor.

The rate and extent of polyprotein processing are the major steps controlling picornavirus gene expression. It is, therefore, important to determine the enzymes responsible for each proteolytic event. The poliovirus protein 3C has been identified as a proteinase which specifically cleaves between Q-G pairs. However, recent data have suggested that 3C precursor polypeptides containing 3C sequences may also have proteolytic capabilities. In this study we have analyzed the cleavage specificities of protein 3C and its precursor, 3CD. We have carried out in vitro translation of genetically altered poliovirus mRNAs to demonstrate that 3CD is required for efficient processing of the P1 capsid precursor to capsid proteins. In addition, we suggest 3CD and 3C process Q-G pairs in the P2 and P3 precursors with similar efficiencies.

Capsid↗
PubMed1991

Antigenic regions of poliovirus type 3/Sabin capsid proteins recognized by human sera in the peptide scanning technique.

We used the peptide scanning technique to identify regions of poliovirus type 3/Sabin capsid proteins that bind antibodies from human immune sera. Several reactive regions were seen in VP1, VP2, and VP3 while peptides resembling VP4 did not bind antibodies. Peptides derived from sequences of the previously known antigenic sites 1 and 3 were recognized to a moderate degree. Peptides imitating the four loops in the closed ends of the beta barrels or the alpha helical CD insertions of VP1, VP2 or VP3, whether exposed in the crystal structure or not, all represented major reactivity in the scans. In VP1 several additional reactive regions were found in the amino terminal quarter of the protein, which is buried in the crystal structure, and in a partially exposed region close to but separated from the carboxy terminus. In VP2 the nonexposed peak activities clustered in a bridge-like structure spanning from the outer to the inner surface of the capsid shell. Likewise, most of the novel antigenic regions of VP3 clustered in an internal location and partially composed of beta sheets with a conserved amino acid sequence. Whether any of the novel antigenic sites is capable of inducing neutralizing antibodies is not known.

Antibodies, Viral↗
PubMed1991

Expression of the major inner capsid protein of the group B rotavirus ADRV: primary characterization of genome segment 5.

A complete cDNA copy of the fifth RNA segment of the human group B rotavirus, ADRV, has been cloned into plasmid AD512. Gene segment 5 contains 1269 bases and encodes one long open reading frame of 391 amino acids beginning at base 31 and terminating at base 1203. The gene 5 polypeptide, expressed in vitro in a rabbit reticulocyte lysate, comigrates with the 44-kDa major inner capsid protein present on EDTA treated ADRV virions. The gene 5 protein is immunoprecipitable by hyperimmune serum to ADRV, human ADRV convalescent serum and by a group B-specific monoclonal antibody. In addition, this protein shares amino acid identity and similarity with the VP6 proteins from group C and group A rotavirus strains. The ADRV VP6 equivalent protein appears to be more closely related to the group C VP6 than the Group A VP6 polypeptide and a common ancestral rotavirus VP6 precursor protein is suggested. As a result, the fifth RNA segment of ADRV defines the major inner capsid protein, or VP6 equivalent, in the group B rotavirus. Expression of the ADRV VP6 equivalent protein is potentially useful for evaluating the prevalence of serum antibodies to group B rotavirus in human and animal populations as well as for generating antibodies for the direct detection of group B rotavirus antigen.

Amino Acid Sequence↗
PubMed1992

Analysis of epitopes on potato leafroll virus capsid protein.

Pepscan hexapeptides prepared to the capsid protein amino acid sequence of potato leafroll luteovirus (PLRV) were tested against both polyclonal and monoclonal antibodies. Twelve continuous epitopes were identified: 11 were detected by two different PLRV polyclonal antisera, but only 4 were detected by both antisera. The 12th epitope reacted with monoclonal antibody BG3. The location of most of the epitopes did not correlate well with antigenic areas predicted by computer algorithms. Comparison of the amino acid sequences of PLRV and southern bean mosaic virus capsid proteins allowed a preliminary assignment of epitopes 4-12 to different regions of the putative S domain of the PLRV subunit. Five out of 14 monoclonal antibodies and both of the polyclonal antisera reacted with epitope 1 at the N-terminus. ELISA data indicated that even though the N-terminus is hydrophobic, it is exposed at the surface of the particles.

Amino Acid Sequence↗
PubMed1992

Characterization of the specificity and genetic restriction of human CD4+ cytotoxic T cell clones reactive to capsid antigen of rubella virus.

Using 11 overlapping synthetic peptides covering more than 95% of the amino acid sequence of capsid protein of rubella virus, 7 CD4+ T cell clones (R10, R11, R18, A2, A10, A11, and A12) isolated from 2 rubella seropositive donors reacted strongly to rubella capsid peptides C6 (residues 119-152), C9 (residues 205-233), or C11 (residues 255-280), respectively, in both proliferation and cytotoxicity assay. Truncated peptides C6E (residues 125-139), C9B (residues 205-216), and C11E (residues 260-272) were shown to be involved directly to the T cell determinants of C6, C9, and C11, respectively. Genetic restriction of these T cell clones was analyzed by using human cell lines with various HLA-DR phenotypes as targets and/or antigen-presenting cells in cytotoxicity assay and/or proliferation assays. The results indicated that the recognition of peptide C6 by T cell clones (R11 and R18) was associated with DRw9 molecule, while the HLA restriction element of the responses of other T cell clones (A2 and A11, A10, and A12) that reacted with peptide C9 or C11 was DR4 molecule. However, there may be a cross-recognition by the T cell clone (A12) between DR1 and DR4 subtypes.

Amino Acid Sequence↗
PubMed1992

Definition of linear antigenic regions of the HPV16 L1 capsid protein using synthetic virion-like particles.

Mice of three haplotypes (H-2d, H-2b, and H-2d/b) were immunized with synthetic HPV16 virus-like particles (VLPs), produced using a vaccinia virus doubly recombinant for the L1 and L2 proteins of HPV16. The resultant anti-VLP antisera recognized HPV16 capsids by ELISA assay and baculovirus recombinant HPV16 L1 and L2 protein on immunoblot. Overlapping peptides corresponding to the HPV16 L1 amino acid sequence were used to define the immunoreactive regions of the L1 protein. The majority of the L1 peptides were reactive with IgG from the mice immunized with the synthetic HPV16 capsids. A computer algorithm predicted seven B epitopes in HPV16 L1, five of which lay within peptides strongly reactive with the murine antisera. The murine anti-VLP antisera failed to react with the two peptides recognized by anti-HPV16L1 monoclonal antibodies raised by others against recombinant L1 fusion protein. We conclude that the immunoreactive epitopes of HPV16 defined using virus-like particles differ significantly from those defined using recombinant HPV16 L1 fusion proteins, which implies that such fusion proteins may not be the antigens to look for HPV16L1 specific immune responses in HPV-infected patients.

Amino Acid Sequence↗
PubMed1993

Detection of foot-and-mouth disease virus RNA in clinical samples and cell culture isolates by amplification of the capsid coding region.

Foot-and-mouth disease is one of the most economically important virus diseases of livestock. Two important requirements for the control of this disease are rapid laboratory diagnosis and epidemiological investigation. The use of the polymerase chain reaction method (PCR) to amplify specific nucleic acid regions offers the unique possibility of combining swift viral detection with the production of genetic material suitable for sequencing and other methods of molecular epidemiological analysis. The sequencing of the region of foot-and-mouth disease virus (FMDV) genome encoding the capsid proteins of the virus (approximately 2260 bps), provides valuable information that adds to the molecular characterisation of an isolate. This paper describes the use of the PCR for the amplification of this region of the FMDV genome from bovine clinical samples and cell culture isolates. Suitable pairs of oligonucleotide primers were selected from the published sequence of FMDV type O1, Kaufbeuren. One primer set amplified 2091 bps of the capsid coding region of all seven serotypes of FMDV. The other primer set amplified 216 bp from this region of FMDV type O1, BFS 1860, in nucleic acid extracts from several clinical samples. Nucleic acid extracts from the picornaviruses, bovine enterovirus and swine vesicular disease virus, which affect the same animals, were not amplified. Direct sequencing was carried out on the amplified fragments and showed that the PCR products were > 98% homologous to published FMDV sequences.

Animals↗
PubMed1993

SCH 38057: a picornavirus capsid-binding molecule with antiviral activity after the initial stage of viral uncoating.

The activity of a new water-soluble molecule, SCH 38057, against picornaviruses is described. SCH 38057 inhibited plaque formation of selected entero- and rhinoviruses in a range of 10.2 to 29.1 microM (50% endpoint) and had a therapeutic index of 10 against poliovirus type 2 (polio 2) in HeLa cells. When administered orally or subcutaneously, SCH 38057 protected mice infected with either coxsackievirus B3 (CVB3) or echovirus-9 from mortality. The molecule provided a low level of protection against thermal inactivation of virus, indicating that SCH 38057 interacts with the picornavirus capsid. Binding studies with [3H]SCH 38057 revealed that the molecule binds to CVB3 and human rhinovirus 14 (HRV14) in a ratio of 29 and 19 molecules per viral particle, respectively. The affinity constant for SCH 38057 binding to CVB3 was 7.0 x 10(-4) M. When added to cultures of infected cells at 3 h after infection, SCH 38057 markedly inhibited viral RNA synthesis. This finding with lack of inhibition of attachment and loss of infectious virus after attachment were interpreted to indicate that, although SCH 38057 binds to the viral capsid, the molecule exerts its antiviral effect after the initial stage of picornavirus uncoating, i.e., after conversion of the 156S infectious viral particle to smaller subviral species.

Animals↗
PubMed1987

Topological organization of Sindbis virus capsid protein in isolated nucleocapsids.

Sindbis virus nucleocapsids were isolated from mature virions by a two-step purification method. Detergent-treated virions were sedimented in sucrose gradients and the nucleocapsid peaks chromatographed on RNase-free Sephadex G-200. The purified nucleocapsids displayed several morphologies when examined in the electron microscope. These morphologies, and the results of double-angle shadowing, suggest that the core of this enveloped virus has the shape of a regular icosahedron with a triangulation number of 4. Peptide mapping of capsid protein obtained from nucleocapsids that had been radioiodinated by a variety of means, indicated that of the four tyrosine residues in the protein, only Tyr180 was exposed at the surface of the icosahedral structure. The other three residues were not exposed on the outer surface of the nucleocapsid shell, nor on the surface of capsid protein itself, implying that they were buried within the folded protein.

Capsid↗
PubMed1989

Nucleotide sequence of capsid protein gene of porcine parvovirus.

Approximately 90% of the genome of porcine parvovirus was cloned into bacterial cells. The nucleotide sequence of the genome from 33 map units (MU) to 95 MU was determined and shown to include the entire gene encoding the capsid proteins. The predicted amino acid sequences of the capsid proteins showed extensive homology to those of other autonomous parvoviruses.

Amino Acid Sequence↗
PubMed1996

Sequence analysis of wheat and oat furovirus capsid protein genes suggests that oat golden stripe virus is a strain of soil-borne wheat mosaic virus.

In northern blots, cDNA probes prepared to soil-borne wheat mosaic virus (SBWMV) RNA-1 and RNA-2 hybridized to RNA-1 and RNA-2, respectively, from a UK isolate of oat golden stripe virus (OGSV), as well as to their homologous RNAs. RT-PCR was used to amplify, clone and sequence a region of about 750 nucleotides spanning the capsid protein gene and part of the readthrough protein on RNA-2 from OGSV, a French isolate of SBWMV and two stable deletion mutants (Lab1 and Okl-7) of SBWMV isolates from Nebraska and Oklahoma respectively. There was very high (96.7-99.1%) nucleotide homology between all these sequences and the wild-type SBWMV sequences from Nebraska and Oklahoma. OGSV was more similar to SBWMV from France and Nebraska than were any of the isolates to SBWMV from Oklahoma. Of the few differences in the deduced amino acid sequences of the capsid proteins from the different isolates, OGSV differed from all SBWMV isolates only in one amino acid (isoleucine for valine at position 88). The high degree of similarity suggests that OGSV may best be classified as an oat strain of SBWMV.

Avena↗
PubMed1992

Production of porcine parvovirus empty capsids with high immunogenic activity.

The VP2 gene of porcine parvovirus was cloned in the baculovirus system and expressed in insect cells. The resulting product was present in high yield. It self-assembled into particles which were structurally and antigenically indistinguishable from regular PPV capsids. A high degree of purity of the recombinant capsids was obtained by ammonium sulphate precipitation of cell lysates. These virus-like particles were used as antigen in the immunization of two pigs. The pigs elicited an immune response which, when assayed by standard serological techniques, was identical to that of a commercial vaccine. The amount of recombinant antigen needed in a vaccine dose was only 3 micrograms in a primary dose and 1.5 micrograms in the booster.

Animals↗
PubMed1996

Cloning and nucleotide sequence of the major capsid proteins of Lactobacillus bacteriophage phi gle.

Bacteriophage phi gle was induced from a lysogenic Lactobacillus strain Gle. phi gle genome is double-stranded DNA of approximately 42.5 kilo-base (kb) pairs. SDS poly-acrylamide gel electrophoresis demonstrated that the phage particles contain 4 major structural (capsid) proteins, gpB, gpG, gpO, and gpP, whose molecular weights (MW) are estimated to be 64, 43, 29 and 26 kilodaltons (kDa), respectively. More than 16 minor proteins ranging from 113 to 9.6 kDa were also detected. The genes for the major capsid proteins were cloned and each DNA sequence was determined. N-terminal amino acid alignments determined by protein sequencing completely coincided with those deduced from the nucleotide sequences.

Amino Acid Sequence↗
PubMed2005

Immunogenicity of enterovirus 70 capsid protein VP1 and its non-overlapping N- and C-terminal fragments.

Currently no practical treatment method or effective virus vaccine is available for acute hemorrhagic conjunctivitis (AHC) caused by enterovirus 70 (EV70). Antibodies to UV-inactivated EV70 (J670/71 epidemic isolate) and to the inclusion bodies of recombinant proteins of full-length EV70 VP1 (GST-VP1m), its non-overlapping terminal fragments N138 (1-138 aa) and C170 (141-310 aa) (or GST-N138m and GST-C170) were developed in rabbits. The anti-EV70 neutralizing activities of the rabbit sera were determined by standard neutralization assays. The antibodies to UV-inactivated EV70, were immuno-reactive with EV70 capsid proteins VP1 and VP3 of four EV70 epidemic isolates (KW/97, T260/74, J670/71 and AE/72) in Western-blot analysis, and immunoprecipitated the capsid proteins VP1 and VP3 from the cell lysates of virus-infected human Chang's conjunctival (HCC) cells. The antibodies to GST-VP1m, GST-N138m and GST-C170, immunoprecipitated only the VP1 proteins of the four EV70 isolates. Anti-EV70 J670/71 antibodies and the antibodies to the three recombinant VP1 proteins were all capable of immunoprecipitating EV70 whole-virus of the four EV70 epidemic isolates grown in HCC cells. The anti-EV70 virion antibodies neutralized EV70 isolates with titers of 6000-10,000 units/ml while the antibodies to GST-VP1m, GST-N138m or GST-C170 neutralized EV70 isolates with titers of 20-320units/ml. The results suggest that (a) immunization with bacterially produced recombinant EV70 VP1 and its non-overlapping N- and C-terminal fragments, was capable of eliciting EV70-neutralizing antibodies; (b) the neutralization titers of antibodies to the recombinant VP1 proteins were lower than that of antibodies to the UV-inactivated EV70 virions; and (c) the non-overlapping N138 and C170 fragments of EV70 VP1 both harbor independent anti-EV70 neutralization antigenic sites.

Antibodies, Viral↗
PubMed2006

Assemblages of simian virus 40 capsid proteins and viral DNA visualized by electron microscopy.

SV40 assembles in the nucleus by addition of capsid proteins to the minichromosome. The VP15VP2/3 capsomer is composed of a pentamer of the major protein VP1 complexed with a monomer of a minor protein, VP2 or VP3. In the capsid, the capsomers are bound together via their flexible carboxy-terminal arms. Our previous studies suggested that the capsomers are recruited to the packaging signal ses via avid interaction with Sp1. During assembly Sp1 is displaced, allowing chromatin compaction. Here we investigated the interactions in vitro of VP1(5)VP2/3 capsomers with the entire SV40 genome, using mutant VP1 deleted in the carboxy-arm that cannot assemble, but retains DNA-binding capacity. EM revealed that VP1(5)VP2/3 complexes bind non-specifically at random locations around the DNA. Sp1 was absent from mature virions. The findings suggest that multiple capsomers attach simultaneously to the viral genome, increasing their local concentration, facilitating rapid, concerted assembly reaction and removal of Sp1.

Binding Sites↗
PubMed2005

2-Ethoxybenzoxazole as a bioisosteric replacement of an ethyl benzoate group in a human rhinovirus (HRV) capsid binder.

A series of pyridazinylpiperidinyl capsid-binding compounds with novel bicyclic substituents were synthesized and screened against human rhinovirus (HRV). Several 2-alkoxy- and 2-alkylthio-benzoxazole and benzothiazole derivatives showed excellent anti-HRV activity. When tested against a panel of 16 representative HRV types the 2-ethoxybenzoxazole derivative 13 was found to have superior HRV activity (median EC(50) 3.88ng/mL) to known capsid-binders Pleconaril and Pirodavir. Compound 13 illustrates that a 2-alkoxybenzoxazole group can be an effective bioisostere for a benzoate ester or benzaldehyde oxime ether functionality.

Benzoates↗