The chemical reactions of influenza virus proteins

Hoyle, L.; Hana, L

doi:10.1002/path.1700920224

Cited by 12 publications

(8 citation statements)

References 7 publications

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“…The method was similar to that described by HOYLE and HA~rA (16). Briefly, virus (HA 30,000--40,000 per ml) was adsorbed onto 2 per cent fowl RBC at 4 ° C for 1 to 2 hours with occasional mixing.…”

Section: Assay O] Virus Elution Ratementioning

confidence: 99%

Effect of Ca++ on the stability of influenza virus neuraminidase

Baker

Gandhi

1976

Archives of Virology

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The neuraminidases of different strains of influenza virus varied in their stability at 37 degrees C. The enzymes of the strains with N1 neuraminidases were found to be unstable during incubation at 37 degrees C whereas the enzymes of the strains with the N2 neuraminidases were stable. Among the strains with N2 neuraminidases, the enzymes of some strains were inactivated during dialysis at 37 degrees C whereas the enzymes of others were stable. This observed loss of enzyme activity during dialysis at 37 degrees C was not restricted to a single substrate as the same loss of enzyme activity was observed irrespective of the size of the substrate used in the assay. The enzymically inactive neuraminidase was found to be non-antigenic and non-immunogenic. The inactivation of the enzyme could be prevented by the addition of Ca++ but not Mg++. Out results suggest that Ca++ is essential for the stability of the enzyme at 37 degrees C. The results would also suggest that the enzymic, antigenic and immunogenic sites are either the same or very closely situated on the surface of the neuraminidase molecule.

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Section: Assay O] Virus Elution Ratementioning

confidence: 99%

Effect of Ca++ on the stability of influenza virus neuraminidase

Baker

Gandhi

1976

Archives of Virology

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confidence: 98%

The chemical reactions of the haemagglutinins and neuraminidases of different strains of influenza viruses: II. Effects of reagents modifying the higher order structure of the protein molecule

Hoyle

1969

J. Hyg.

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In previous work (Hoyle & Hana, 1966) it was found that the enzymic activity of the DSP and LEE strains of influenza virus was reduced by agents acting on disulphide bonds. The results, however, tended to be irregular, except in the case of mercuric chloride, these irregularities being attributed to reversibility of the reaction with many of the chemical reagents used. More recent work using dithiothreitol (Cleland, 1964) which reacts completely and irreversibly with the disulphide bond have shown that the disulphide bonds in the virus proteins are inaccessible to attack except under conditions permitting some disruption of hydrogen bonds. A study has therefore been made of the effects on the virus properties produced by reagents acting on non-covalent bonds alone and in combination with dithiothreitol. METHODSIn this work purified 'virus concentrate' preparations have been used, prepared as described in the previous paper (Hoyle, 1969). Two mixtures were first made, one consisting of equal volumes of virus concentrate and buffer pH 8-0, and the second of virus concentrate and 1/100 dithiothreitol in buffer pH 8-0. The two mixtures in 0*05 ml. amounts were then mixed with 0x15 ml. of buffer pH 8-0 containing amounts of urea or guanidine sufficient to give final concentrations of 0, 4 M and 6 M urea or 2 M, 4 M and 6 M guanidine. Mixtures were held at 200 C. for 30 min. and were then diluted to 2 ml. with buffer pH 6-0. Haemagglutinin titres were then measured and neuraminidase activity assessed by the elution test as described in the previous paper (Hoyle, 1969). Each virus was therefore exposed to concentrations of urea of 0, 4 M and 6 M, and of 2 M, 4 M and 6 M guanidine, alone and in combination with 1/800 dithiothreitol.In addition the action of mercuric chloride was tested by exposing virus dilution preparations to 1/10,000 HgCl2 at pH 6-0 for 2 hr. at 370 C. RESULTSIn contrast to the results obtained with reagents reacting directly with amino acids in the active centres of the virus haemagglutinin and neuraminidase, very

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“…Isolation of phosphatidylcholine [7], of phosphatidylserine [8] and of plasmid DNA [9]; labelling of DNA by nick translation [10] and of serum albumin with fluorescein isothiocyanate [11]; encapsulation of labelled plasmid DNA or of the fluorescent conjugate of bovine serum albumin with fluorescein isothiocyanate into liposomes by reverse-phase evaporation [12]; preparation of protoplasts [13] and transformation of protoplasts with naked DNA [14], were done according to published methods.…”

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confidence: 99%