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Novel Chemical Ligands to Ebola Virus and Marburg Virus Nucleoproteins Identified by Combining Affinity Mass Spectrometry and Metabolomics Approaches.

Fu X, Wang Z, Li L, Dong S, Li Z, Jiang Z, Wang Y, Shui W - Sci Rep (2016)

Bottom Line: Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP.Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources.In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development.

View Article: PubMed Central - PubMed

Affiliation: College of Biotechnology, Tianjin University of Science &Technology, Tianjin 300457, China.

ABSTRACT
The nucleoprotein (NP) of Ebola virus (EBOV) and Marburg virus (MARV) is an essential component of the viral ribonucleoprotein complex and significantly impacts replication and transcription of the viral RNA genome. Although NP is regarded as a promising antiviral druggable target, no chemical ligands have been reported to interact with EBOV NP or MARV NP. We identified two compounds from a traditional Chinese medicine Gancao (licorice root) that can bind both NPs by combining affinity mass spectrometry and metabolomics approaches. These two ligands, 18β-glycyrrhetinic acid and licochalcone A, were verified by defined compound mixture screens and further characterized with individual ligand binding assays. Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP. Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources. In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development.

No MeSH data available.


Related in: MedlinePlus

Potential interaction of new ligands with the RNA-binding groove of Ebola virus NP.(A) The crystal structure of EBOV NPcore containing the N-lobe (in blue) and C-lobe (in brown). The RNA-binding pocket surrounded by several residues is marked by a circle and enlarged in the side stereoview. (B) Primary sequence alignment of members of the filoviridae family. Residues in the RNA-binding groove are indicated by yellow arrows. Docking model of GC7 (C) and GC13 (D) interacting with the RNA-binding groove of EBOV NP.
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f4: Potential interaction of new ligands with the RNA-binding groove of Ebola virus NP.(A) The crystal structure of EBOV NPcore containing the N-lobe (in blue) and C-lobe (in brown). The RNA-binding pocket surrounded by several residues is marked by a circle and enlarged in the side stereoview. (B) Primary sequence alignment of members of the filoviridae family. Residues in the RNA-binding groove are indicated by yellow arrows. Docking model of GC7 (C) and GC13 (D) interacting with the RNA-binding groove of EBOV NP.

Mentions: The crystal structure of EBOV NP (PDB code 4Z9P) solved in a previous study is featured by two identifiable lobes, an N-lobe spanning NP residues 36 to 240 and a C-lobe from 241 to 351 that are connected together by a flexible hinge located within the C-lobe31. From this structure, a highly positively charged groove located at the interface between the N- and C-lobes constitutes a potential RNA-binding pocket (Fig. 4A). In this pocket, the major positive-charged crevice involves residues K160, K171, R174, and K248 and the adjacent minor positive-charged region consists of residues R205, K211, and R29831. These key basic residues are highly conserved across not only the Ebola virus genus but the whole filovirus family as well (Fig. 4B). They are reported to play essential roles in viral RNA encapsidation and EBOV proliferation in host cells11323334.


Novel Chemical Ligands to Ebola Virus and Marburg Virus Nucleoproteins Identified by Combining Affinity Mass Spectrometry and Metabolomics Approaches.

Fu X, Wang Z, Li L, Dong S, Li Z, Jiang Z, Wang Y, Shui W - Sci Rep (2016)

Potential interaction of new ligands with the RNA-binding groove of Ebola virus NP.(A) The crystal structure of EBOV NPcore containing the N-lobe (in blue) and C-lobe (in brown). The RNA-binding pocket surrounded by several residues is marked by a circle and enlarged in the side stereoview. (B) Primary sequence alignment of members of the filoviridae family. Residues in the RNA-binding groove are indicated by yellow arrows. Docking model of GC7 (C) and GC13 (D) interacting with the RNA-binding groove of EBOV NP.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940736&req=5

f4: Potential interaction of new ligands with the RNA-binding groove of Ebola virus NP.(A) The crystal structure of EBOV NPcore containing the N-lobe (in blue) and C-lobe (in brown). The RNA-binding pocket surrounded by several residues is marked by a circle and enlarged in the side stereoview. (B) Primary sequence alignment of members of the filoviridae family. Residues in the RNA-binding groove are indicated by yellow arrows. Docking model of GC7 (C) and GC13 (D) interacting with the RNA-binding groove of EBOV NP.
Mentions: The crystal structure of EBOV NP (PDB code 4Z9P) solved in a previous study is featured by two identifiable lobes, an N-lobe spanning NP residues 36 to 240 and a C-lobe from 241 to 351 that are connected together by a flexible hinge located within the C-lobe31. From this structure, a highly positively charged groove located at the interface between the N- and C-lobes constitutes a potential RNA-binding pocket (Fig. 4A). In this pocket, the major positive-charged crevice involves residues K160, K171, R174, and K248 and the adjacent minor positive-charged region consists of residues R205, K211, and R29831. These key basic residues are highly conserved across not only the Ebola virus genus but the whole filovirus family as well (Fig. 4B). They are reported to play essential roles in viral RNA encapsidation and EBOV proliferation in host cells11323334.

Bottom Line: Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP.Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources.In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development.

View Article: PubMed Central - PubMed

Affiliation: College of Biotechnology, Tianjin University of Science &Technology, Tianjin 300457, China.

ABSTRACT
The nucleoprotein (NP) of Ebola virus (EBOV) and Marburg virus (MARV) is an essential component of the viral ribonucleoprotein complex and significantly impacts replication and transcription of the viral RNA genome. Although NP is regarded as a promising antiviral druggable target, no chemical ligands have been reported to interact with EBOV NP or MARV NP. We identified two compounds from a traditional Chinese medicine Gancao (licorice root) that can bind both NPs by combining affinity mass spectrometry and metabolomics approaches. These two ligands, 18β-glycyrrhetinic acid and licochalcone A, were verified by defined compound mixture screens and further characterized with individual ligand binding assays. Accompanying biophysical analyses demonstrate that binding of 18β-glycyrrhetinic acid to EBOV NP significantly reduces protein thermal stability, induces formation of large NP oligomers, and disrupts the critical association of viral ssRNA with NP complexes whereas the compound showed no such activity on MARV NP. Our study has revealed the substantial potential of new analytical techniques in ligand discovery from natural herb resources. In addition, identification of a chemical ligand that influences the oligomeric state and RNA-binding function of EBOV NP sheds new light on antiviral drug development.

No MeSH data available.


Related in: MedlinePlus