Glycoproteins viral

The mechanism of inhibition has not been characterized, but it is probably related to the ionophoretic properties of these antibiotics. Monensin has been shown to inhibit the intracellular transport of viral membrane proteins of cells infected with Semliki Forest vims (169). The formation of syncytia, normally observed when T-lymphoblastoid cell line (CEM) cells are cocultivated with human immunodeficiency vims (HlV-l)-infected T-ceU leukemia cell line (MOLT-3) cells, was significantly inhibited in the presence of monensin (170). This observation suggests that the viral glycoproteins in the treated cells were not transported to the cell surface from the Golgi membrane. 

After the virus has attached to CD4 and chemokine receptors, another viral glycoprotein (gp41) assists with viral fusion to the cell and internalization of the viral contents. The viral contents include single-stranded RNA, an RNA-dependent DNA polymerase (also known as reverse transcriptase), and other enzymes. Using the single-stranded viral RNA as a template, reverse transcriptase synthesizes a complementary strand of DNA. The single-stranded viral RNA is removed from the newly formed DNA strand by ribonuclease H, and reverse transcriptase completes the synthesis of double-stranded DNA. The... 

Kim, Y. J. Freas, A. Fenselau, C. Analysis of viral glycoproteins by MALDI-TOF mass spectrometry. Anal. Chem. 2001, 73,1544—1548. 

The life cycle of many viruses, including retroviruses, depends on viral proteases that cleave viral glycoproteins into individual polypeptides, and these enzymes are necessary for viral replication. NO can inactivate coxsackievirus [136]. Since cysteine proteases are critical for the virulence and replication of many viruses, nitrosation of viral cysteine proteases may be a mechanism of antiviral host defense. NO mediates nitrosation of cysteine and aspartyl proteases of HIV-1, and it was suggested that this... 

These new estimates of the particle weight change the number of copies of the viral glycoprotein per viral particle. The polypeptides (capsid, 1, E2, and 3) are present in equimolar amounts (Garoff et al., 1974). Since 56.6% of the virus is protein (leaving out the carbohydrate content) the viral particle (using a molecular weight of 41-42 x 10 ) should contain about 180 copies of each protein. 

Fig. 1. Nucleotide sequence of the SFV 26 S RNA (top row), the corresponding amino acid sequence (middle row), and the amino acid sequence of the Sindbis virus structural proteins (bottom row). Nucleotides are numbered from the 5 end of the RNA molecule and all amino adds from the amino terminus of each protein. The amino- and the carboxyl-terminal ends of each protein are indicated hy arrows, glycosylation sites by triangles, and membrane-spanning regions of the viral glycoproteins by underlines for Sindbis virus and overlines for SFV. Amino acids in boxes are negatively charged (Asp and Glu), and those circled are positively charged (Lys and Arg). Some restriction endonuclease cleavage sites are shown on the nucleotide sequence. The alignment of the amino acid...

C. Intracellular Transport of the Viral Glycoproteins 1. Posttranslational Modifications... 

A successful tool in the early studies of metabolic pathways was blocking the pathway at some specific point. This could be done by the use of either mutants or inhibitors. Schekman et al have isolated a number of yeast mutants with blocks in their secretion pathway (Schekman, 1982). It is not yet known which proteins these mutations affect, but this is clearly a most promising approach for identifying those components involved in transport. In animal cells there are no cellular mutants with blocks in the intracellular transport of protein from the ER to the cell surface. There are, however, genetic diseases which affect the routing of lysosomal enzymes to the lysosomes (Neufeld et al, 1975 Sly and Fischer, 1982). For viruses it has been possible to isolate temperature-sensitive mutants in which a mutation in the viral glycoprotein arrests... 

Application of Lectins for the Detection of Ab to Viral Glycoproteins in the Blood Serum... 

Studies on the glycosylation of one viral protein in different cells,102,103 or of different viral proteins in one cell type,104-108 or comparison of carbohydrate chains of a viral glycoprotein and an immuno-... 

The best known inhibitors of glycosylation of proteins interfere with the lipid-dependent steps.35,228 Substances that specifically block reactions taking place after the transfer of the oligosaccharide to the protein are little known. As several, incompletely (or differently) glycosylated, viral glycoproteins arc still biologically active (see Section IV), these substances would escape the screening procedure based on... 

Cerulenin inhibits formation of polyisoprenol, probably by uncom-petitively inhibiting HMG-CoA synthetase.250 It strongly inhibited production of Rous-sarcoma virus by infected, chick-embryo cells, but an effect on the viral glycoproteins was not observed.251 Other effects of cerulenin, such as its inhibition of fatty acid synthesis, may have caused inhibition of virus production. The inhibition, by cerulenin, of secretion of proteins by bacilli has been noted for some time, but no satisfactory explanation has as yet been offered (see Ref. 252, and ref-... 

Some compounds known to be inhibitors of peptidoglycan formation in bacteria have proved also to inhibit the lipid pathway of glyco-sylation of proteins. Moreover, these compounds show antiviral activity, because the maturation of enveloped virus in eukaryotic cells is impaired if glyeosylation of viral glycoproteins is inhibited (see Section IV). 

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