The hepatitis B virus X protein is a potent AMP kinase.

The hepatitis B virus X-protein (HBx) has been expressed in Escherichia coli both as an unfused protein and with an N-terminal hexaHis-containing fusion sequence. Both forms of HBx, after purification, displayed a potent AMP kinase activity, in which HBx phosphorylates AMP to ADP, using ATP as the exclusive phosphate donor. We also found that HBx has previously unreported GTPase and GTP-ADP nucleoside diphosphate kinase activities.

Characterization of the mRNA encoding a proline-rich 37-kilodalton glycoprotein from the excretory-secretory products of Trichostrongylus colubriformis.

A glycoprotein, with apparent molecular weight in SDS-polyacrylamide gels of 37 kDa, has been isolated from the excretory-secretory (ES) products of the adult stage of Trichostrongylus colubriformis, a parasitic nematode. This protein is the major ES product recognized in immunoblots by lymph from a naturally infected sheep. A synthetic oligonucleotide, based on peptide sequence data from a digest of the purified protein was used to successfully screen a cDNA library.

The isolation, characterization and cloning of a globin-like, host-protective antigen from the excretory-secretory products of Trichostrongylus colubriformis.

An 18-kDa component from the excretory-secretory (ES) products of adults of Trichostrongylus colubriformis was isolated and characterized, and was shown to induce 60-84% protection of guinea pigs from challenge infection following a single intraperitoneal injection. Amino-terminal sequence analysis of gel-purified protein enabled oligonucleotides to be synthesized and used to screen a lambda gt10 cDNA library made from young adult worm mRNA, and to synthesize full-length clones from cDNA using the polymerase chain reaction (PCR). The full-length clones coded for a 20-kDa precursor protein of 173 amino acids which had a strongly hydrophobic leader sequence of 15 residues.

Molecular characterisation of a protective, 11-kDa excretory-secretory protein from the parasitic stages of Trichostrongylus colubriformis.

An 11-kDa protein occurring as a major component of the non-glycosylated fraction of 4th larval stage (L4) and adult Trichostrongylus colubriformis excretory-secretory (ES) fluid has been found to be highly protective in guinea pigs, an alternate host for T. colubriformis. The protein has been purified, characterised and partly sequenced.

Does variation in palatability affect the postprandial response in energy expenditure?

The impact of variation in palatability on diet- and sucrose-induced thermogenesis was studied in two experiments with 24 healthy young normal-weight subjects, 12 men and 12 women. In the first study, subjects received at random in duplicate either a normal liquid test meal (2,000 kJ, 12% protein, 33% fat, 55% carbohydrate), or an iso-energetic test meal made highly unpalatable with kinin. The difference in palatability did not have a significant impact on postprandial metabolism.

Characterization, cloning and host-protective activity of a 30-kilodalton glycoprotein secreted by the parasitic stages of Trichostrongylus colubriformis.

The helminth Trichostrongylus colubriformis is a parasitic nematode infecting the small intestine of sheep. We report the isolation and characterization of a 30-kDa glycoprotein capable of partially protecting guinea-pigs against the parasite. This glycoprotein is secreted by the L4 and adult parasitic stages of the worm.

Characterization of the major immunogen in the excretory-secretory products of exsheathed third-stage larvae of Trichostrongylus colubriformis.

The excretory-secretory products of exsheathed third-stage larvae of Trichostrongylus colubriformis conferred some protection to guinea pigs against homologous challenge. A glycoprotein with an apparent molecular mass of approximately 94 kDa was the dominant immunogen in post-exsheathment products. Immunoblots revealed IgG antibodies to this glycoprotein in sera from multiply-infected guinea pigs and some sheep, and in sera of guinea pigs after three truncated infections which had been restricted by anthelmintic treatments to development of the third parasitic stage.

Evolution of the Hong Kong influenza A sub-type. Structural relationships between the haemagglutinin from A/duck/Ukraine/1/63 (Hav 7) and the Hong Kong (H3) haemagglutinins.

The relationship between the haemagglutinin from the influenza virus A/duck/Ukraine/1/63 (Hav 7) and the human Hong Kong variants (H3) has been investigated. Amino-acid-sequence analysis shows that the Hav 7 haemagglutinin closely resembles the 1968 human H3 haemagglutinin in structure. However, the number of amino-acid-sequence differences (23) suggest that the Hong Kong haemagglutinin gene did not come directly from A/duck/Ukraine/1/63 but from a virus derived from it by antigenic drift during the period 1963-1968.

Amino acid sequence and oligosaccharide distribution of the haemagglutinin from an early Hong Kong influenza virus variant A/Aichi/2/68 (X-31).

The amino acid sequence and oligosaccharide distribution for the haemagglutinin from the early Hong Kong influenza virus A/Aichi/2/68 (X-31) was investigated. The two polypeptide chains, HA1 and HA2, were fragmented by CNBr and enzymic digestion, and the amino acid sequence of each small peptide was deduced by comparing its chromatographic behaviour, electrophoretic mobility, amino acid composition and N-terminus with that of the corresponding peptide of the haemagglutinin of known structure from the influenza-virus variant A/Memphis/102/72. Those peptides in which changes were detected were sequenced fully.

Composition and sequence studies show that A/duck/Ukraine/1/63 haemagglutinin (Hav7) belongs to the Hong Kong (H3) subtype.

The haemagglutinin chains HA1 and HA2 from the avian influenza virus A/duck/Ukraine/1/63 (Hav7, Neq2) have been subjected to amino acid analysis and N-terminal sequencing. Automated sequenator analysis of HA1 (40 cycles), after enzymic removal of the N-terminal pyroglutamic acid blocking group, and HA2 (43 cycles) showed that the Hav7 haemagglutinin closely resembled the human Hong Kong (H3) haemagglutinins including the presence of the characteristic extended 10 residue sequence at the N-terminus of HA1. These findings, together with the amino acid compositions for both chains, demonstrate that the Hav7 haemagglutinin is structurally similar to the Hong Kong (H3) haemagglutinins.

The location of the bromelain cleavage site in a Hong Kong influenza virus Haemagglutinin.

The site of bromelain cleavage in the haemagglutinin of the Hong Kong influenza virus A/Memphis/102/72 has been determined by using a diagonal peptide mapping procedure on the thermolytic digest of amidated BHA. The data show that bromelain cleavage removes the C-terminal 46 residues from HA2, and that the new carboxyl-terminal residue of BHA2 is Gly 175. This is close to the beginning of the hydrophobic membrane-interacting sequence that starts at residue 183.

The amino acid sequence of a Hong Kong influenza haemagglutinin light (HA2) chain.

The amino acid sequence of the Hong Kong haemagglutinin light chang (HA2:222 residues) is nearly complete, lacking only the definition of a highly aggregated region near the carboxyl terminal end of the chain. This unsequenced area of approx. 25 residues occurs near the carboxyl terminal end of cyanogen bromide peptide CN-I, whose structure determination is discussed in this paper.

Antigenic determinants of influenza virus hemagglutinin. V. Antigenicity of the HA2 chain.

All the polypeptide fragments obtained by cyanogen bromide cleavage of the hemagglutinin from A/Memphis/102/72 influenza virus were examined for their ability to bind to IgG raised against purified virus. Within the hemagglutinin heavy chain the only fragment displaying antigenicity is HA1CN1, which comprises the amino-terminal 168 amino acid residues. By the use of a sensitive radioimmunoassay in which the antigen is unlabeled, it was shown that the light chain is also antigenic.

Carbohydrate composition of the oligosaccharide units of the haemagglutinin from the Hong Kong influenza virus A/Memphis/102/72.

The haemagglutinin from the Hong Kong influenza virus A/Memphis/102/72 contains seven oligosaccharide units attached to asparagine residues 8, 22, 38, 81, 165 and 285 in the heavy chain (HA1) and to residue 154 in the light chain (HA2). The single oligosaccharide unit in HA2 and four of the oligosaccharide units of HA1 (at residues 8, 22, 38 and 81) contain the four monosaccharides N-acetylglucosamine, mannose, galactose and fucose and are of the N-acetyllactosamine (or 'complex') type. The two other oligosaccharide units on HA1 are of the oligomannoside (or 'simple') type and contain only two residues of N-acetylglucosamine and five or six residues of mannose.

Influenza virus haemagglutinin. Structural predictions suggest that the fibrillar appearance is due to the presence of a coiled-coil.

Predictions of secondary structure for the two chains HA1 and HA2 of the haemagglutinin from the Hong Kong influenza virus A/Memphis/102/72 reveal a striking contrast between the potential conformations of the two chains. HA1 is predicted to be rich in beta-structure while HA2 is highly helical. The predictions further suggest that coiled-coil type interactions between the central helical segments of the HA2 chains may hold the haemagglutinin monomers together in the virus.

Amino acid sequence of cyanogen bromide fragment CN2 from Hong Kong influenza haemagglutinin heavy chain.

The amino acid sequence of cyanogen bromide peptide CN2 from the heavy chain (HA1) of the haemagglutinin of the Hong Kong variant A/Memphis/102/72 has been obtained by direct, automated sequence analysis on the whole fragment and by manual dansyl-Edman degradation of tryptic, peptic and chymotryptic peptides. It was found to contain 92 amino acid residues, including a large, insoluble, tryptic core peptide (residues 62-87). It did not contain any half-cystine residues or carbohydrate.

Amino acid sequence changes in the haemagglutinin of A/Hong Kong (H3N2) influenza virus during the period 1968--77.

Haemagglutinin molecules from nine strains of A/Hong Kong/68 (H3N2) influenza virus, isolated between 1968 and 1977, were examined for changes in amino acid sequences. At least 18 changes, 9 of which were located precisely, occurred in the soluble tryptic peptides of the large haemagglutinin polypeptide (HA1) during this period. These peptides contained 262 residues (82% of HA1).

Antigenic determinants of influenza virus hemagglutinin. II. Antigenic reactivity of the isolated N-terminal cyanogen bromide peptide of A/Memphis/72 hemagglutinin heavy chain.

Gel filtration of a cyanogen bromide digest of pure intact hemagglutinin from A/Memphis/102/72 influenza virus allowed the isolation of a variety of fragments. One of these fragments consists of three cyanogen bromide peptides (CNl and CN3 from HA1, and CNl from HA2) which remain linked together by disulphide bonds. This fragment was found to be antigenically active, as it was able to form antigen-antibody complexes (detected by affinity chromatography of radioiodinated peptide-IgG mixtures on protein A-Sepharose) with IgG directed against the protein moiety of viral hemagglutinin.