Human parainfluenza type 3 (hPIV-3) is one of the leading causes of lower respiratory tract disease in children. In their Communication (DOI: 10.1002/anie.201412243), M. von Itzstein, I. M. El-Deeb, P. Guillon, L. M. G. Chavas, and co-workers investigate the catalytic mechanism of hPIV-3 haemagglutinin-neuraminidase (HN) and determine that it is a retaining glycohydrolase. Moreover hPIV-3 HN utilizes a highly conserved tyrosine residue to form a transient covalent bond with the anomeric carbon of the substrate. Finally a novel sialic acid derivative showed potency in virus blockade assays.
