Neuraminidase-associated plasminogen recruitment enables systemic spread of natural avian Influenza viruses H3N1
Fig 5
Sequence comparisons and phylogenetic analysis of the CK/BE/1940/19 neuraminidase (N1).
(A) Amino acid alignment of positions described as responsible for neuraminidase mediated plasminogen binding. The loss of the Asn at position 130 and therefore the loss of the N-glycosylation site (blue isolate name), as described for WSN, has also been found in the CK/BE/1940/19 isolate but not in the comparative DK/DE/2555/06 isolate (red dots). First Belgian H3N1 isolate from January still has intact N-glycosylation site (green dot). Database research (www.fludb.de) including all full length N1-sequences without duplicates reveals only 24 of 11417 sequences to have no asparagine at this position. These 24 isolates (listed in detail in S2 Table) are shown in the (B) phylogenetic tree (calculated as a maximum likelihood tree using RAxML with a bootstrap value of 1000 cycles) together with the available N1-sequences from the Belgian H3N1 outbreak (n = 9) (both blue, except the Belgian January isolate) from 2019 and other representative N1 scaffold sequences (black).