scholarly journals Epitope mapping of human respiratory syncytial virus 22K transcription antitermination factor: role of N-terminal sequences in protein folding

2005 ◽  
Vol 86 (4) ◽  
pp. 1103-1107 ◽  
Author(s):  
Blanca García-Barreno ◽  
John Steel ◽  
Monica Payá ◽  
Luis Martínez-Sobrido ◽  
Teresa Delgado ◽  
...  

The reactivity of a panel of 12 monoclonal antibodies raised against the human respiratory syncytial virus 22 kDa (22K) protein was tested by Western blotting with a set of 22K deletion mutants. The results obtained identified sequences in the C-terminal half of the 22K polypeptide required for integrity of most antibody epitopes, except for epitope 112, which was lost in mutants with short N-terminal deletions. This antibody, in contrast to the others, failed to immunoprecipitate the native 22K protein, indicating that the N terminus of this protein is buried in the native molecule and exposed only under the denaturing conditions of Western blotting. In addition, N-terminal deletions that abolished reactivity with monoclonal antibody 112 also inhibited phosphorylation of the 22K protein previously identified at Ser-58 and Ser-61, suggesting that the N terminus is important in regulating the 22K protein phosphorylation status, most likely as a result of its requirement for protein folding.

Virology ◽  
1993 ◽  
Vol 195 (1) ◽  
pp. 239-242 ◽  
Author(s):  
Josefa Garcı́a ◽  
Blanca Garcı́a-Barreno ◽  
Isidoro Martinez ◽  
José A. Melero

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 750
Author(s):  
Raj Kalkeri ◽  
Govinda Bhisetti ◽  
Nagraj Mani

Human respiratory syncytial virus (HRSV) causes bronchiolitis and pneumonia. The role of methyltransferase (MTase) activity of HRSV polymerase in viral replication is unknown. Literature reviews of similar viral MTases and homology- modeling of RSV MTase bound to GTP and S-adenosylmethionine (SAM) have shown sequence similarity and the conserved catalytic residues (K-D-K-E) and the SAM-binding (GXGXG) domain. Combined with the recent reports of the importance of 2’O methylation of viral RNAs in the host innate immune response evasion, and its proposed role in viral replication, HRSV MTase holds promise as a potential antiviral target. Further biological validation of HRSV MTase could facilitate the discovery of novel HRSV antivirals targeting MTase enzyme activity.


F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 750
Author(s):  
Raj Kalkeri ◽  
Govinda Bhisetti ◽  
Nagraj Mani

Human respiratory syncytial virus (HRSV) causes bronchiolitis and pneumonia. The role of methyltransferase (MTase) activity of HRSV polymerase in viral replication is unknown. Literature reviews of similar viral MTases and homology- modeling of RSV MTase bound to GTP and S-adenosylmethionine (SAM) have shown sequence similarity and the conserved catalytic residues (K-D-K-E) and the SAM-binding (GXGXG) domain. Combined with the recent reports of the importance of 2’O methylation of viral RNAs in the host innate immune response evasion, and its proposed role in viral replication, HRSV MTase holds promise as a potential antiviral target. Further biological validation of HRSV MTase could facilitate the discovery of novel HRSV antivirals targeting MTase enzyme activity.


Virology ◽  
1998 ◽  
Vol 252 (1) ◽  
pp. 137-148 ◽  
Author(s):  
Emily Burke ◽  
Lesley Dupuy ◽  
Cynthia Wall ◽  
Sailen Barik

2006 ◽  
Vol 87 (12) ◽  
pp. 3637-3642 ◽  
Author(s):  
Ana Asenjo ◽  
Enrique Calvo ◽  
Nieves Villanueva

The human respiratory syncytial virus (HRSV) P protein is phosphorylated, with different turnover rates, at several serine (S) and threonine (T) residues. The role of phosphothreonines in viral RNA synthesis was studied by using P protein substitution variants and the HRSV-based minigenome pM/SH. By using liquid chromatography coupled to ion-trap mass spectrometry, it was found that P protein T108 was phosphorylated by addition of a high-turnover phosphate group. This phosphorylation occurs in P protein expressed transiently and during HRSV infection. The results suggest that phosphorylation at P protein T108 affects M2-1 transcriptional activities, because this modification prevents interaction between the P and M2-1 proteins. Therefore, P protein phosphorylation–dephosphorylation at T108 could distinguish the role of the P protein in viral transcription and replication.


2006 ◽  
Vol 87 (5) ◽  
pp. 1267-1273 ◽  
Author(s):  
C. Mekseepralard ◽  
G. L. Toms ◽  
E. G. Routledge

Monoclonal antibodies (mAbs) to conserved epitopes on the G glycoprotein of human respiratory syncytial virus (HRSV) subgroup A fail to neutralize the virus in cell culture in the absence of complement, but are protective in rodent models of infection. They may have potential as prophylactic agents in human infants. In order to investigate the role of Fc-dependent pathways in protection by one such antibody, 1C2, the VH and VL genes were isolated by RT-PCR and assembled with human κ light-chain and human γ1 heavy-chain constant-region genes to form two mouse–human chimaeras, which were expressed in NS0 cells. One of the chimaeras carried a wild-type γ1 chain, whilst the other had an aglycosyl mutation in the CH2 domain rendering the antibody defective in complement activation and FcγR binding. Whilst both chimaeric antibodies exhibited similar avidity for HRSV in ELISA, only the fully glycosylated wild type was capable of neutralizing the virus in the presence of complement. In mice passively immunized with either murine or wild-type γ1 chimaeric antibody, no virus could be recovered from the lungs 4 days after intranasal inoculation of HRSV. In mice immunized with the aglycosyl γ1 chimaera, however, virus was present in the lungs following challenge, although virus titres were significantly reduced compared with controls (P<0·005). These results indicate that the protective effect of this antibody is mediated by both Fc-dependent and Fc-independent pathways.


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