Dataset Information

Structure and mutagenesis of the parainfluenza virus 5 hemagglutinin-neuraminidase stalk domain reveals a four-helix bundle and the role of the stalk in fusion promotion.

ABSTRACT: Paramyxovirus entry into cells requires the fusion protein (F) and a receptor binding protein (hemagglutinin-neuraminidase [HN], H, or G). The multifunctional HN protein of some paramyxoviruses, besides functioning as the receptor (sialic acid) binding protein (hemagglutinin activity) and the receptor-destroying protein (neuraminidase activity), enhances F activity, presumably by lowering the activation energy required for F to mediate fusion of viral and cellular membranes. Before or upon receptor binding by the HN globular head, F is believed to interact with the HN stalk. Unfortunately, until recently none of the receptor binding protein crystal structures have shown electron density for the stalk domain. Parainfluenza virus 5 (PIV5) HN exists as a noncovalent dimer-of-dimers on the surface of cells, linked by a single disulfide bond in the stalk. Here we present the crystal structure of the PIV5-HN stalk domain at a resolution of 2.65 Å, revealing a four-helix bundle (4HB) with an upper (N-terminal) straight region and a lower (C-terminal) supercoiled part. The hydrophobic core residues are a mix of an 11-mer repeat and a 3- to 4-heptad repeat. To functionally characterize the role of the HN stalk in F interactions and fusion, we designed mutants along the PIV5-HN stalk that are N-glycosylated to physically disrupt F-HN interactions. By extensive study of receptor binding, neuraminidase activity, oligomerization, and fusion-promoting functions of the mutant proteins, we found a correlation between the position of the N-glycosylation mutants on the stalk structure and their neuraminidase activities as well as their abilities to promote fusion.

SUBMITTER: Bose S

PROVIDER: S-EPMC3233124 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Structure and mutagenesis of the parainfluenza virus 5 hemagglutinin-neuraminidase stalk domain reveals a four-helix bundle and the role of the stalk in fusion promotion.

Bose Sayantan S Welch Brett D BD Kors Christopher A CA Yuan Ping P Jardetzky Theodore S TS Lamb Robert A RA

Journal of virology 20111012 24

Paramyxovirus entry into cells requires the fusion protein (F) and a receptor binding protein (hemagglutinin-neuraminidase [HN], H, or G). The multifunctional HN protein of some paramyxoviruses, besides functioning as the receptor (sialic acid) binding protein (hemagglutinin activity) and the receptor-destroying protein (neuraminidase activity), enhances F activity, presumably by lowering the activation energy required for F to mediate fusion of viral and cellular membranes. Before or upon recep ...[more]

PMID: 21994464

Similar Datasets

Project description:Virus-specific interaction between the attachment protein (HN) and the fusion protein (F) is prerequisite for the induction of membrane fusion by parainfluenza viruses. This HN-F interaction presumably is mediated by particular amino acids in the HN stalk domain and those in the F head domain. We found in the present study, however, that a simian virus 41 (SV41) F-specific chimeric HPIV2 HN protein, SCA, whose cytoplasmic, transmembrane, and stalk domains were derived from the SV41 HN protein, could not induce cell-cell fusion of BHK-21 cells when coexpressed with an SV41 HN-specific chimeric PIV5 F protein, no. 36. Similarly, a headless form of the SV41 HN protein failed to induce fusion with chimera no. 36, whereas it was able to induce fusion with the SV41 F protein. Interestingly, replacement of 13 amino acids of the SCA head domain, which are located at or around the dimer interface of the head domain, with SV41 HN counterparts resulted in a chimeric HN protein, SCA-RII, which induced fusion with chimera no. 36 but not with the SV41 F protein. More interestingly, retroreplacement of 11 out of the 13 amino acids of SCA-RII with the SCA counterparts resulted in another chimeric HN protein, IM18, which induced fusion either with chimera no. 36 or with the SV41 F protein, similar to the SV41 HN protein. Thus, we conclude that the F protein specificity of the HN protein that is observed in the fusion event is not solely defined by the primary structure of the HN stalk domain.It is appreciated that the HN head domain initially conceals the HN stalk domain but exposes it after the head domain has bound to the receptors, which allows particular amino acids in the stalk domain to interact with the F protein and trigger it to induce fusion. However, other regulatory roles of the HN head domain in the fusion event have been ill defined. We have shown in the current study that removal of the head domain or amino acid substitutions in a particular region of the head domain drastically change the F protein specificity of the HN protein, suggesting that the ability of a given HN protein to interact with an F protein is defined not only by the primary structure of the HN stalk domain but also by its conformation. This notion seems to account for the unidirectional substitutability among rubulavirus HN proteins in triggering noncognate F proteins.

Project description:Membrane fusion by the parainfluenza viruses is induced by virus-specific functional interaction between the attachment protein (HN) and the fusion (F) protein. This interaction is thought to be mediated by transient contacts between particular amino acids in the HN stalk domain and those in the F head domain. However, we recently reported that replacement of specified amino acids at or around the dimer interface of the HN head domain remarkably affected the F protein specificity. We then intended to further investigate this issue in the present study and revealed that the HPIV2 HN protein can be converted to an SV41 HN-like protein by substituting at least nine amino acids in the HPIV2 HN head domain with the SV41 HN counterparts in addition to the replacement of the stalk domain, indicating that specified amino acids in the HN head domain play very important roles in determining the specificity of the HN-F interaction. On the other hand, we previously reported that the PIV5 F protein can be converted to an SV41 F-like protein by replacing 21 amino acids in the head domain of the PIV5 F protein with those of the SV41 F protein. We then intended to further investigate this issue in the present study and found that replacement of 15 amino acids in the stalk domain in addition to the replacement of the 21 amino acids in the head domain of the PIV5 F protein resulted in creation of a more SV41 F-like protein, indicating that specified amino acids in the F stalk domain play important roles in determining the specificity of the HN-F interaction. These results suggest that the conformations of the HN stalk domain and the F head domain are dependent on the structures of the HN head domain and the F stalk domain, respectively. Presumably, the conformations of the former domains, which are considered directly involved in the HN-F interaction, can be modified by subtle changes in the structure of the latter domains, resulting in an altered specificity for the interacting partners.

Project description:UNLABELLED:Paramyxoviruses, enveloped RNA viruses that include human parainfluenza virus type 3 (HPIV3), cause the majority of childhood viral pneumonia. HPIV3 infection starts when the viral receptor-binding protein engages sialic acid receptors in the lung and the viral envelope fuses with the target cell membrane. Fusion/entry requires interaction between two viral surface glycoproteins: tetrameric hemagglutinin-neuraminidase (HN) and fusion protein (F). In this report, we define structural correlates of the HN features that permit infection in vivo. We have shown that viruses with an HN-F that promotes growth in cultured immortalized cells are impaired in differentiated human airway epithelial cell cultures (HAE) and in vivo and evolve in HAE into viable viruses with less fusogenic HN-F. In this report, we identify specific structural features of the HN dimer interface that modulate HN-F interaction and fusion triggering and directly impact infection. Crystal structures of HN, which promotes viral growth in vivo, show a diminished interface in the HN dimer compared to the reference strain's HN, consistent with biochemical and biological data indicating decreased dimerization and decreased interaction with F protein. The crystallographic data suggest a structural explanation for the HN's altered ability to activate F and reveal properties that are critical for infection in vivo. IMPORTANCE:Human parainfluenza viruses cause the majority of childhood cases of croup, bronchiolitis, and pneumonia worldwide. Enveloped viruses must fuse their membranes with the target cell membranes in order to initiate infection. Parainfluenza fusion proceeds via a multistep reaction orchestrated by the two glycoproteins that make up its fusion machine. In vivo, viruses adapt for survival by evolving to acquire a set of fusion machinery features that provide key clues about requirements for infection in human beings. Infection of the lung by parainfluenzavirus is determined by specific interactions between the receptor binding molecule (hemagglutinin-neuraminidase [HN]) and the fusion protein (F). Here we identify specific structural features of the HN dimer interface that modulate HN-F interaction and fusion and directly impact infection. The crystallographic and biochemical data point to a structural explanation for the HN's altered ability to activate F for fusion and reveal properties that are critical for infection by this important lung virus in vivo.

Dataset Information

Structure and mutagenesis of the parainfluenza virus 5 hemagglutinin-neuraminidase stalk domain reveals a four-helix bundle and the role of the stalk in fusion promotion.

Publications

Structure and mutagenesis of the parainfluenza virus 5 hemagglutinin-neuraminidase stalk domain reveals a four-helix bundle and the role of the stalk in fusion promotion.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets