Search PubMed⌕ Search

Biomedical subjects

C W Ward

Publications and source records attributed to C W Ward.

At least 127 records · Page 7Linked to original sources
PubMed1980

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↗
PubMed1980

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. All 1/2-cystine residues present in HA2 occur in CN-I, as a proximal cluster involving residues 137, 144 and 148, and as a distal cluster involving four other 1/2-cystine within peptides. The single glycosylated asparagine in HA2 also occurs in CN-I; the carbohydrates moiety is complex. The structure of HA2 is discussed in terms of its properties, and compared with published data from haemagglutinins from other influenza strains.

Amino Acid Sequence↗
PubMed1980

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. Inhibition studies have localized the activity to the HA2CN1 region, which comprises the carboxy-terminal 90 amino acids. The determinant on HA2 is shown to be subtype specific.

Antibodies, Viral↗
PubMed1979

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. The three cyanogen bromide peptides present in this disulphide-linked fragment were separated by gel filtration, carried out under reducing conditions, and tested for antigenic activity after controlled reoxidation of the individual peptides. Only one cyanogen bromide peptide, CNl from HA1, showed significant binding to antibody. The results indicate that antigenic activity of A/Mem/1O2/72 hemagglutinin resides within the N-terminal 170 amino acid residues of the hemagglutinin heavy chain.

Antibodies, Viral↗
PubMed1978

The carboxyl-terminal sequence of the heavy chain of a Hong Kong influenza haemagglutinin.

The reduced carboxymethylated heavy chain (HA1) of a Hong Kong influenza haemagglutinin (H3) was digested with cyanogen bromide to give five peptides. The sequences of three of these peptides, together with the sequences of two methionine overlap peptides were combined to give the C-terminal 68-residue sequence of the heavy chain. Threonine is the C-terminal residue of the heavy chain, an unexpected result in view of the generation of the heavy and light chains by the proteolytic cleavage of a pro-haemagglutinin during virus assembly. Three half-cystine residues occur close together at positions 24, 48 and 52 residues in from the C-terminus. A carbohydrate group is attached to an asparagine residue 44 residues from the C-terminus; it contains 5 residues mannose and 2 residues glucosamine.

Amino Acid Sequence↗
PubMed1976

Properties of the major carboxypeptidase in the larvae of the webbing clothes moth, Tineola bisselliella.

The larvae of the webbing clothes moth, Tineola bisselliella contain two carboxypeptidases (EC 3.4.12-) and one of these has been purified by preparative polyacrylamide gel electrophoresis. Its pH optimum for the hydrolysis of N-benzyloxycarbonyl-glycyl-leucine was pH 7.5-7.7 and its molecular weight as judged by gel filtration was 72 000. It is strongly inhibited by disopropylfluorophosphate, thiol reagents and some metal cations and also by 1:10 phenanthroline but not EDTA. Km and V values for the hydrolysis of 13 N-acyl dipeptides were determined. The enzyme has a strong preference for neutral aliphatic amino acid residues and does not hydrolyse C-terminal proline, arginine or lysine. It is a true carboxypeptidase, requiring an L-amino acid in the C-terminal position, with a free carboxyl group and hydrolysing peptide substrates consecutively from the C-terminal end. Dipeptides are cleaved much more slosly than tripeptides or N-acyl dipeptides.

Animals↗
PubMed1975

Aminopeptidases in webbing clothes moth larvae. Properties and specificities of the enzymes of intermediate electrophoretic mobility.

The major group of aminopeptidases (EC 3.4.11.-) of intermediate electrophoretic mobility, from Tineola bisselliella larvae, hav been fractionated into six bands by preparative polyacrylamide gel electrophoresis and the properties of these fractions investigated. They resemble each other in their pH optima of 8.2, their molecular weight of 240 000, their responses to various active site inhibitors and metal cations, and their specificities towards seventeen L-amino-acyl-beta-naphthylamide substrates. The derivatives of methionine, leucine, alanine, lysine, arginine and glutamic acid were those most rapidly hydrolysed. They appear to be true aminopeptidases hydrolysing amino acid amides, dipeptides and oligopeptides from the N-terminal end.

Amino Acids↗
PubMed1975

Properties and specificity of the major anionic trypsin-like enzyme in the keratinolytic larvae of the webbing clothes moth.

The major form of the trypsin-like proteinases from the larvae of the webbing clothes moth Tineola bisselliella has been further purified and some of its properties investigated. It differs from bovine trypsin in several respects. It is anionic at neutral pH, is very stable at alkaline pH, has no requirement for calcium ions for this stability and is very sensitive to urea. It resembles vertebrate trypsins in its complete inhibition by diisopropylfluorophosphate, its pH optimum of 8.5 for hydrolysis of benzoyl-arginine p-nitroanilide and its cleavage specificity against glucagon and the beta-chain of S-carboxymethyl insulin.

Amino Acids↗