PubMed:6192436 JSONTXT

{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/6192436","sourcedb":"PubMed","sourceid":"6192436","source_url":"http://www.ncbi.nlm.nih.gov/pubmed/6192436","text":"Sequential mutations in hemagglutinins of influenza B virus isolates: definition of antigenic domains.\nComparative analysis of the amino acid sequences of hemagglutinins (HAs) of influenza B/Lee/40, B/Md/59, and B/HK/73 viruses has allowed examination of the molecular basis of antigenic variation in type B viruses. As seen with influenza type A viruses, antigenic drift in influenza B viruses proceeds mostly through the accumulation of amino acid substitutions within the HA1 portion of the HA molecule. However, the rate of variation observed among the influenza B virus HAs appears to be significantly lower than the observed rate of variation among influenza A virus HAs. The overall rate of amino acid change in the HA1s of the influenza B viruses studied is 2% per 10 years, whereas the HA1s of H3 influenza A viruses vary by 9.2% per 10 years. The sequences of the influenza B HAs were also examined in relation to the three-dimensional model for the A/Aichi/2/68 HA. When the primary amino acid sequences are compared, it appears that most of the important structural features of the type A HAs--such as the sialic acid binding site, the disulfide linkages, and the stem structure of the trimer--are conserved in the influenza B virus HAs. Regions are also identified where extensive amino acid substitutions have occurred among the three antigenically distinct influenza B virus HAs. The locations of these areas in the B HA structure correspond to antigenic regions proposed for the A virus HAs. In addition, modulation of antigenic regions in B virus HAs may also occur through amino acid deletions and variation in glycosylation sites.","tracks":[{"project":"IAV-Glycan_IAV_H3","denotations":[{"id":"T1","span":{"begin":1118,"end":1129},"obj":"sialic acid"}],"attributes":[{"subj":"T1","pred":"source","obj":"IAV-Glycan_IAV_H3"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"IAV-Glycan_IAV_H3","color":"#93eca2","default":true}]}]}}