title: Diversity in glycosaminoglycan binding amongst hMPV G protein lineages.
abstract: We have previously shown that hMPV G protein (B2 lineage) interacts with cellular glycosaminoglycans (GAGs). In this study we examined subtypes A1, A2 and B1 for this interaction. GAG-dependent infectivity of available hMPV strains was demonstrated using GAG-deficient cells and heparin competition. We expressed the G protein ectodomains from all strains and analysed these by heparin affinity chromatography. In contrast to the B2 lineage, neither the A2 or B1 G proteins bound to heparin. Sequence analysis of these strains indicated that although there was some homology with the B2 heparin-binding domains, there were less positively charged residues, providing a likely explanation for the lack of binding. Although sequence analysis did not demonstrate well defined positively charged domains in G protein of the A1 strain, this protein was able to bind heparin, albeit with a lower affinity than G protein of the B2 strain. These results indicate diversity in GAG interactions between G proteins of different lineages and suggest that the GAG-dependency of all strains may be mediated by interaction with an alternative surface protein, most probably the conserved fusion (F) protein. Analysis of both native and recombinant F protein confirmed that F protein binds heparin, supporting this conclusion.
authors.affiliation: Department of Microbiology and Infectious Diseases, Flinders University, Flinders Medical Centre, Bedford Park, SA 5042, Australia. penelope.adamson@health.sa.gov.au
authors.forename: Penelope
authors.initials: P
authors.lastname: Adamson
authors.forename: Sutthiwan
authors.initials: S
authors.lastname: Thammawat
authors.forename: Gamaliel
authors.initials: G
authors.lastname: Muchondo
authors.forename: Tania
authors.initials: T
authors.lastname: Sadlon
authors.forename: David
authors.initials: D
authors.lastname: Gordon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002845:Chromatography; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D006801:Humans; D029121:Metapneumovirus / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D011485:Protein Binding; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014760:Viral Fusion Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D053585:Virus Attachment
chemical_list: C484233:G glycoprotein, human metapneumovirus; D006023:Glycoproteins; D006025:Glycosaminoglycans; D014760:Viral Fusion Proteins; D014764:Viral Proteins; D006493:Heparin