Proteins viral

Reverse transcriptase (from avian or murine RNA tumour viruses) [9068-38-6] [EC 2.7.7.49]. Purified by solubilising the virus with non-ionic detergent. Lysed virions were adsorbed on DEAE-cellulose or DEAE-Sephadex columns and the enzyme eluted with a salt gradient, then chromatographed on a phosphocellulose column and enzyme activity eluted in a salt gradient. Purified from other viral proteins by affinity chromatography on a pyran-Sepharose column. [Verna Biochim Biophys Acta 473 1 7977 Smith Methods Enzymol 65 560 1980 see commercial catalogues for other transcriptases.]... 

X-ray studies at 22.5 A resolution of murine polyomavlrus by 1. Rayment and D.L.D. Caspar at Brandeis University confirmed the presence of these 72 capsomers at the expected positions, but even at low resolution the pentagonal shape of all 72 capsomers was evident (Figure 16.22). They concluded that each capsomer must be a pentameric assembly of the major viral subunit, known as viral protein 1 (VPl). Each of the 60 icosahedral asymmetric units contains 6 VPl subunits, not 7, and the complete shell contains 360 VPl subunits. The 12 VPl pentamers centered on icosahedral fivefold axes are identically related to their five neighbors, but the 60 pentamers centered on pseudosixfold positions "see" each of their 6 neighbors quite differently (Figure 16.23). How can such diversity of interaction be incorporated into the bonding properties of just one type of protein subunit, without compromising specificity and accuracy of assembly ... 

A variety of cellular and viral proteins contain fatty acids covalently bound via ester linkages to the side chains of cysteine and sometimes to serine or threonine residues within a polypeptide chain (Figure 9.18). This type of fatty acyl chain linkage has a broader fatty acid specificity than A myristoylation. Myristate, palmitate, stearate, and oleate can all be esterified in this way, with the Cjg and Cjg chain lengths being most commonly found. Proteins anchored to membranes via fatty acyl thioesters include G-protein-coupled receptors, the surface glycoproteins of several viruses, and the transferrin receptor protein. 

Bacterial or viral proteins linking T-cell receptors and MHC molecules through simultaneous interaction with the constant domains of all MHC class II molecules and of T-cell receptor (3-chains. Hence, superantigens are polyclonal T-cell activators most likely involved in the development of autoimmune diseases. 

Trauger SA, Junker T, Siuzdak G (2003) Investigating Viral Proteins and Intact Viruses with Mass Spectrometry. 225 257-274... 

Rhinovirus, like poliovirus, synthesizes a large precursor protein from which all of the mature viral proteins are generated. Two viral proteases are involved in these cleavages 2A protease cleaves the polyprotein precursor at its own N terminus, while the 3C protease is responsible for additional cleavage events to generate the mature viral proteins. Both proteases can release themselves from the polyprotein precursor. Cleavage by 3C occurs between Gln/Gly, but flanking sequences affect efficiency (reviewed in Racaniello 2001). 

Apart from offering a new and highly specific approach to the inhibition of herpesviruses, this new mechanism of action could potentially also have beneficial immunological consequences. During treatment with BAY 38-4766, viral protein synthesis continues, but due to the lack of monomeric genomic length DNA, only empty particles (dense bodies) can be formed. It is conceivable that these non-infections viral particles could aid the establishment of an antiviral immune response, leading to better control of the virus by the host. This mechanism appears... 

Underwood M, Harvey R, Stanat S, Hemphill M, Miller T, Drach J, Townsend L, Biron K (1998) Inhibition of human cytomegalovirus DNA maturation by a benzimidazole ribonucleoside is mediated through the UL89 gene product. J Virol 72 717-725 Van Maele B, Debyser Z (2005) HlV-1 integration an interplay between HIV-1 integrase, cellular, and viral proteins. AIDS Rev 7 26 3... 

Okui N, Kobayashi N, Kitamura Y (1998) Production of uninfectious human immunodeficiency virus type 1 containing viral protein R fused to a single-chain antibody against viral integrase. J Virol 72 6960-6964... 

The mechanisms of HIV-associated DSP are incompletely understood. Over the years, various hypotheses have been put forward, but recent data suggest that multiple mechanisms are likely to play a role in neuronal or axonal injury in DSP. These processes may be mediated by direct neurotoxicity of HIV or secreted viral proteins such as the envelope glycoprotein gpl20, or by indirect mechanisms... 

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