Margaret N. Short

Studies on alfalfa mosaic virus: I. The protein and nucleic acid

Abstract The molecular weight of the alfalfa mosaic virus (AMV) protein subunit was determined from amino acid analyses and specific staining for certain amino acids on peptide maps from tryptic and chymotryptic digests of the protein. A subunit molecular weight of 32,600 was confirmed by estimations of C-terminal and N-terminal residues and of the tryptophan content. AMV nucleic acid consisted of four components with sedimentation values of 24.3, 20.0, 17.3, and 12.7 S. The molecular weights of these components were estimated.

Variations in the composition of two strains of tobacco mosaic virus in relation to their host

Abstract The amino acid compositions of the cowpea and sunn hemp strains of tobacco mosaic virus when isolated from Nicotiana tabacum and Phaseolus vulgaris were determined. When isolated from tobacco the cowpea and sunn hemp mosaic virus proteins had amino acid analyses that closely resembled type strain of tobacco mosaic virus and showed approximately 23 amino acid replacements from their bean forms. From discrepancies in the values obtained for the carboxyl end groups of virus preparations made from bean plants, and the loss of the C-terminal threonine from tobacco mosaic virus when it was incubated with bean sap, it was concluded that bean sap contained a carboxypeptidase-like enzyme.

The amino acid composition, antigenicity, and other characteristics of the satellite viruses of tobacco necrosis virus

Abstract Three strains of the satellite (SV) of tobacco necrosis virus (TNV) were compared antigenically and in their ability to multiply with the help of different strains of TNV. Their antigenic specificity was not influenced by the strain of TNV but depended on the particular strain of SV used in the mixture. Antigenically the three strains were distinctly different, and this was reflected in the 49 changes in the amino acid composition of SV 1 and SV 2 . SV 1 and SV 2 multiplied well in mechanically inoculated leaves, whereas SV 3 did best in tobacco roots infected by the aid of the vector Olpidium brassicae . An ambient temperature of 36 °, which inhibited the multiplication of TNV, also affected SV. All strains crystallized readily and virus was lost in crystals during purification unless care was taken. From amino acid analysis and two-dimensional peptide maps, the molecular weight of the protein subunit of SV 1 was found to be 22,800 and to contain 208 amino acid residues. Of the 208 amino acid residues, 182 were accounted for in tryptic peptides separated by ion exchange and Sephadex chromatography. In the TNV and SV association, the RNA of SV codes for its coat protein. On the basis of the triplet code, the coding for the coat protein would require 624 of the 1200 nucleotides, and therefore SV can code for another protein. The help required by SV from TNV is discussed.

The primary structure of papaya mosaic virus coat protein

The amino acid sequence of the coat protein of the potexvirus papaya mosaic virus (PMV) has been determined, using a combination of the Edman degradation procedure (manual and automated) and mass spectrometry. The amino acid sequence is compared with that of the coat protein of potato virus X (PVX) as reported (S. Yu. Morozov, V. M. Zakhariev, B. K. Chernov, V. S. Prasolov, Yu. V. Kozlov, J. G. Atabekov, and K. G. Skyabin, Dokl. Acad. Nauk, SSSR 271, 211-215,1983). PMV has 73 of 211 amino acid residues in common with PVX and has 25 fewer residues in the polypeptide chain. Also 10 of a possible 16 proline residues are in similar positions in both proteins, including a sequence of 3 prolines at the carboxyl end. Furthermore, the 2 cysteine residues in PMV correspond with 2 of the 3 cysteines in PVX.

The amino acid sequence of the cowpea strain of tobacco mosaic virus protein

The amino acid sequence of the coat protein of the cowpea strain of tobacco mosaic virus (cowpea virus) has been determined. The tryptic peptide overlaps were obtained by digesting the protein with chymotrypsin and separating and analysing the lysine-and arginine-containing chymotryptic peptides. The primary structure of cowpea virus protein has been found to differ markedly from that of any other known strain of tobacco mosaic virus, and contains 3 amino acid residues more and 96 amino acid changes from the type strain. The significance of the distribution of those areas of the protein in which the amino acid residues are the same for all naturally occurring strains and chemically induced mutants of tobacco mosaic virus so far studied and the residues that form the important carboxyl-carboxylate pairs are discussed.

Variation in amino acid composition of legumin from Pisum

Abstract Pisum; Leguminosae: pea: amino acid composition: seed storage proteins: legumin.

Narcissus mosaic virus: a potexvirus with an encapsidated subgenomic messenger RNA for coat protein

Narcissus-mosaic-virus RNA is translated into a coat -protein-sized product in wheat-germ cell-free extracts. This protein was shown to be very similar to authentic coat protein by partial proteolysis in SDS/polyacrylamide-gel electrophoresis, and by serology. Fractionation of the RNA revealed a small RNA molecule of approx. 840 nucleotides, which alone coded for the coat protein. This subgenomic RNA was found to be encapsidated in a short virus particle.

The purification, N-terminal amino acid sequence and some other properties of an αM-subunit of legumin from the pea (Pisum sativum L.)

Abstract An αM-subunit of legumin from Pisum sativum has been purified from a genotype which showed no αM-subunit heterogeneity on two-dimensional isofocusing/electrophoresis gels. N-terminal sequence analysis of the subunit showed it to be homologous to the acidic subunits of glycinin, from Glycine max, and particularly similar to glycinin subunit A2. Amino acid analysis showed the αM-subunit to contain three cysteine and three methionine residues per subunit, plus 14 lysine and 39 arginine. Fewer than the expected number of tryptic peptides from the αM-subunit were resolved by two-dimensional peptide mapping, but the expected number could be detected by peptide mapping of αM-subunits which had been hydrolysed with the arginine-specific protease from mouse submaxillary gland.

The tryptic peptides and terminal sequences of the protein from the cowpea strain of tobacco mosaic virus.

The use of ion exchange chromatography, gel filtration, and paper electrophoresis for the separation of the peptides obtained by tryptic digestion of the cowpea strain of tobacco mosaic virus protein is described. The amino acid compositions of the 13 tryptic peptides obtained were determined and accounted for 159 residues compared with the 158 found for type tobacco mosaic virus protein. The only tryptic peptide that cowpea tobacco mosaic virus protein and type tobacco mosaic virus protein have in common is asparaginyl-arginine despite the fact that the former is very similar to type tobacco mosaic virus protein in a number of its properties. The amino terminal sequence was found to be acetyl alanyl-tyrosine and the carboxyl terminal sequence was confirmed as alanine preceded by threonine.

Biochemical and serological comparisons between carnation yellow fleck virus and sugar beet yellows virus protein subunits.

Abstract Carnation yellow fleck virus is serologically related to sugar beet yellow virus. Amino acid analyses and tryptic peptide maps indicate about 50 amino acid differences between the proteins from the two viruses.