The adenovirus protease is activated by a virus-coded disulphide-linked peptide

Webster, Ailsa; Hay, Ronald T.; Kemp, Graham D.

doi:10.1016/0092-8674(93)90053-s

Cited by 140 publications

(154 citation statements)

References 29 publications

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“…The adenovirus 23K proteinase is also stimulated by a peptide cofactor -in this case an 11 aa peptide derived from the C terminus of protein pVI (Webster et al, 1993). The k cat of the enzyme is increased some 350-fold when incubated with an equimolar concentration of cofactor peptide (Mangel et al, 1996).…”

Section: Ns3 Proteinase (I) Identification Of the Ns3 Proteolytic Domainmentioning

confidence: 99%

Virus-encoded proteinases of the Flaviviridae.

Ryan¹,

Monaghan²,

Flint³

1998

Journal of General Virology

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Section: Ns3 Proteinase (I) Identification Of the Ns3 Proteolytic Domainmentioning

confidence: 99%

Virus-encoded proteinases of the Flaviviridae.

Ryan¹,

Monaghan²,

Flint³

1998

Journal of General Virology

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“…If disrupted wild-type virus is treated with DNase, proteinase activity is lost but can be restored upon addition of Ad2 DNA. A second cofactor was shown to be a plasminsensitive virion protein which turned out to be the 11-aminoacid peptide from the C-terminus of the precursor to virion protein VI, pVIc [8,9].…”

Section: Introductionmentioning

confidence: 99%

Different modes of inhibition of human adenovirus proteinase, probably a cysteine proteinase, by bovine pancreatic trypsin inhibitor

et al. 1996

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The type of proteinase and the nature of the active site of the human adenovirus proteinase are unknown. For these reasons we produced an inhibitor prof'de of the enzyme. Enzyme activity in disrupted virions was inhibited by several serinespecific as well as cysteine-specific proteinase inhibitors. Of the inhibitors that worked, the most useful potentially in illuminating the nature of the active site was bovine pancreatic trypsin inhibitor (BPTI), and for this reason we extensively characterized the interaction with BPTI. In disrupted virions, the enzyme is irreversibly inhibited by BPTI with a Ki of 35 nM and a ki of 6.2×10 _4 s -1. One reason enzyme activity is inhibited is that BPTI, a basic protein, precipitates the viral DNA, a cofactor of enzyme activity. In vitro with purified components, BPTI acts as a competitive inhibitor (Ki 2 IJNI) of the recombinant proteinase complexed with its l 1-amino-acid cofactor pVIc. The recombinant endoproteinase is heat labile whereas its ll-amino-acid cofactor is heat stable. We estimate there are about 50 molecules of proteinase per virus particle.

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“…It has been proposed that the activity of the viral protease is greatly enhanced by a disulphide bond interchange between the dimeric form of the 11 amino acid pVIc peptide and the enzyme (Webster et al, 1993). In our experience the enzyme has not always required activation by pVIc, possibly because in the course of purification the enzyme achieved the active redox state (Rancourt et aI., 1994(Rancourt et aI., , 1995Diouri et al, 1995).…”

Section: Redox Modulation Of Enzyme Activitymentioning

confidence: 78%

“…The enzyme has a unique sequence unrelated to other proteases. Instead of being activated by proteolysis of an inactive zymogen as most other proteases, the Ad2 protease remains intact and appears to be activated by an 11-amino-acid cleavage product (dubbed pVIc) of viral protein pre-VI (Mangel et al, 1993 ;Webster et al, 1993). Activation was proposed to occur via a disulphide exchange mechanism between the disulphide linked pVIc dimer and one of the eight cysteines present in the Ad2 protease (Webster et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

“…Instead of being activated by proteolysis of an inactive zymogen as most other proteases, the Ad2 protease remains intact and appears to be activated by an 11-amino-acid cleavage product (dubbed pVIc) of viral protein pre-VI (Mangel et al, 1993 ;Webster et al, 1993). Activation was proposed to occur via a disulphide exchange mechanism between the disulphide linked pVIc dimer and one of the eight cysteines present in the Ad2 protease (Webster et al, 1993). Mutagenesis of two conserved cysteines (C104, C126) did not completely abrogate activation by pVIc (Rancourt et al, 1994;Grierson et al, 1994;unpublished results).…”

Section: Introductionmentioning

confidence: 99%

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Adenovirus Type 2 Endoprotease: Isoforms and Redox Effects

Keyvani-Amineh

Diouri

Tihanyi³

et al. 1996

Journal of General Virology

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The cysteine protease encoded by adenovirus type 2 contains eight cysteines, some of which are involved in catalysis and enzyme activation. Here we investigated the effects of oxidation, mercaptoethanol, dithiothreitol, diamide and protein disulphide isomerase on wild-type and mutant enzymes. Three isoforms of the enzyme were detected in infected cells and a fourth in preparations of purified recombinant enzyme. The latter isoform was absent in preparations of enzyme mutated at any of the three conserved cysteines, C-104, C-122 and C-126. Enzyme activity could be stimulated by agents other than the authentic activating peptide (pVIc), such as cysteamine, though less efficiently. Diamide at low concentrations stimulated the activity of the tsl enzyme, but inhibited both tsl and wild-type enzyme at higher concentrations. Protein disulphide isomerase failed to restore enzyme activity to the oxidized isoform. The present studies in combination with previous results using mutants appeared to rule out amino acids C-67, C-122, C-126 and C-127, leaving the two remaining semi-conserved C-17 and C-40 and the conserved C-104 as potential candidates for binding peptide pVIc.

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The adenovirus protease is activated by a virus-coded disulphide-linked peptide

Cited by 140 publications

References 29 publications

Virus-encoded proteinases of the Flaviviridae.

Virus-encoded proteinases of the Flaviviridae.

Different modes of inhibition of human adenovirus proteinase, probably a cysteine proteinase, by bovine pancreatic trypsin inhibitor

Adenovirus Type 2 Endoprotease: Isoforms and Redox Effects

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