Dataset Information

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

ABSTRACT: The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with membrane fusion. The F protein is synthesized as a precursor (F0) that must be cleaved by a host protease to form a biologically active molecule, F1,F2. Cleavage of F protein is a prerequisite for fusion and virus infectivity. Cleavage creates a new N terminus on F1 that contains a hydrophobic region, known as the FP, which intercalates target membranes during F protein refolding. The crystal structure of the soluble ectodomain of the uncleaved form of PIV5 F is known; here we report the crystal structure of the cleavage-activated prefusion form of PIV5 F. The structure shows minimal movement of the residues adjacent to the protease cleavage site. Most of the hydrophobic FP residues are buried in the uncleaved F protein, and only F103 at the newly created N terminus becomes more solvent-accessible after cleavage. The conformational freedom of the charged arginine residues that compose the protease recognition site increases on cleavage of F protein.

SUBMITTER: Welch BD

PROVIDER: S-EPMC3478641 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

Welch Brett D BD Liu Yuanyuan Y Kors Christopher A CA Leser George P GP Jardetzky Theodore S TS Lamb Robert A RA

Proceedings of the National Academy of Sciences of the United States of America 20120910 41

The paramyxovirus parainfluenza virus 5 (PIV5) enters cells by fusion of the viral envelope with the plasma membrane through the concerted action of the fusion (F) protein and the receptor binding protein hemagglutinin-neuraminidase. The F protein folds initially to form a trimeric metastable prefusion form that is triggered to undergo large-scale irreversible conformational changes to form the trimeric postfusion conformation. It is thought that F refolding couples the energy released with memb ...[more]

PMID: 23012473

Similar Datasets

Project description:Human respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (HPIV3) are major pediatric respiratory pathogens that lack vaccines. A chimeric bovine/human PIV3 (rB/HPIV3) virus expressing the unmodified, wild-type (wt) RSV fusion (F) protein from an added gene was previously evaluated in seronegative children as a bivalent intranasal RSV/HPIV3 vaccine, and it was well tolerated but insufficiently immunogenic for RSV F. We recently showed that rB/HPIV3 expressing a partially stabilized prefusion form (pre-F) of RSV F efficiently induced "high-quality" RSV-neutralizing antibodies, defined as antibodies that neutralize RSV in vitro without added complement (B. Liang et al., J Virol 89:9499-9510, 2015, doi:10.1128/JVI.01373-15). In the present study, we modified RSV F by replacing its cytoplasmic tail (CT) domain or its CT and transmembrane (TM) domains (TMCT) with counterparts from BPIV3 F, with or without pre-F stabilization. This resulted in RSV F being packaged in the rB/HPIV3 particle with an efficiency similar to that of RSV particles. Enhanced packaging was substantially attenuating in hamsters (10- to 100-fold) and rhesus monkeys (100- to 1,000-fold). Nonetheless, TMCT-directed packaging substantially increased the titers of high-quality RSV-neutralizing serum antibodies in hamsters. In rhesus monkeys, a strongly additive immunogenic effect of packaging and pre-F stabilization was observed, as demonstrated by 8- and 30-fold increases of RSV-neutralizing serum antibody titers in the presence and absence of added complement, respectively, compared to pre-F stabilization alone. Analysis of vaccine-induced F-specific antibodies by binding assays indicated that packaging conferred substantial stabilization of RSV F in the pre-F conformation. This provides an improved version of this well-tolerated RSV/HPIV3 vaccine candidate, with potently improved immunogenicity, which can be returned to clinical trials. IMPORTANCE:Human respiratory syncytial virus (RSV) and human parainfluenza virus type 3 (HPIV3) are major viral agents of acute pediatric bronchiolitis and pneumonia worldwide that lack vaccines. A bivalent intranasal RSV/HPIV3 vaccine candidate consisting of a chimeric bovine/human PIV3 (rB/HPIV3) strain expressing the RSV fusion (F) protein was previously shown to be well tolerated by seronegative children but was insufficiently immunogenic for RSV F. In the present study, the RSV F protein was engineered to be packaged efficiently into vaccine virus particles. This resulted in a significantly enhanced quantity and quality of RSV-neutralizing antibodies in hamsters and nonhuman primates. In nonhuman primates, this effect was strongly additive to the previously described stabilization of the prefusion conformation of the F protein. The improved immunogenicity of RSV F by packaging appeared to involve prefusion stabilization. These findings provide a potently more immunogenic version of this well-tolerated vaccine candidate and should be applicable to other vectored vaccines.

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.

Dataset Information

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

Publications

Structure of the cleavage-activated prefusion form of the parainfluenza virus 5 fusion protein.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets