Identification of a Linear Heparin Binding Domain for Human Respiratory Syncytial Virus Attachment Glycoprotein G

Abstract

Respiratory syncytial virus (RSV) is the leading cause of lower respiratory tract disease in infants and young children worldwide. Infection is mediated, in part, by an initial interaction between attachment protein (G) and a highly sulfated heparin-like glycosaminoglycan (Gag) located on the cell surface. Synthetic overlapping peptides derived from consensus sequences of the G protein ectodomain from both RSV subgroups A and B were tested by heparin-agarose affinity chromatography for their abilities to bind heparin. This evaluation identified a single linear heparin binding domain (HBD) for RSV subgroup A (184A→T198) and B (183K→K197). The binding of these peptides to Vero cells was inhibited by heparin. Peptide binding to two CHO cell mutants (pgsD-677 and pgsA-745) deficient in heparan sulfate or total Gag synthesis was decreased 50% versus the parental cell line, CHO-K1, and decreased an average of 87% in the presence of heparin. The RSV-G HBD peptides were also able to inhibit homologous and heterologous virus infectivity of Vero cells. These results indicate that the sequence184A/183K→198T/K197for RSV subgroups A and B, respectively, defines an important determinant of RSV-G interactions with heparin.

Respiratory syncytial virus entry and how to block it

“…The G protein has been shown to bind glycosaminoglycans (GAGs), which are unbranched disaccharide polymers linked to transmembrane proteins on the surface of many mammalian cell types 87,88 . This interaction is primarily mediated by a stretch of positively charged amino acids located between the two mucin-like domains of G, referred to as the heparin-binding domain 89 . However, variants of G lacking the heparin-binding domain retain some heparinase-sensitive binding to cells, suggesting that other regions of G may bind weakly to GAGs 87 .…”

Perspective on the host response to human metapneumovirus infection: what can we learn from respiratory syncytial virus infections?

“…the attachment (G) and fusion (F) proteins. RSV infects respiratory epithelium by interaction of heparinbinding domains on these surface proteins with glycosaminoglycans (GAGs) on the cell surface [40,41]; however, G protein contributes to the majority of virus binding [42,43]. In addition, the non-glycosylated, central conserved region of the G protein contains a CX3C chemokine motif at amino acid positions 182-186 that is capable of interacting with the CX3C chemokine receptor, CX3CR1, and facilitating infection [44].…”

Structure of the parainfluenza virus 5 F protein in its metastable, prefusion conformation

“…The attachment proteins interact with different cellular receptors. For example, SV5 HN protein binds sialic acid, measles virus H protein interacts with CD46 or CDw150/SLAM (refs 4, 5), Nipah and Hendra virus G proteins bind to Ephrin B2 (refs 6, 7) and RSV G protein binds heparin sulphate 8 . Although the cellular receptors differ, in most paramyxoviruses the homotypic attachment protein is required to trigger F-mediated membrane fusion at the right time and right place 9,10 .…”