Giuseppe
Emeritus
[Source: US National Library of Medicine, (LINK). Edited.]
J Virol. 2010 May 12. [Epub ahead of print]
Functional analysis of influenza H5N1 nucleoprotein tail loop reveals amino acids that are crucial for oligomerization and ribonucleoprotein activities.
Chan WH, Ng AK, Robb NC, Lam MK, Chan PK, Au SW, Wang JH, Fodor E, Shaw PC. - Department of Biochemistry and Centre for Protein Science and Crystallography, Molecular Biotechnology Programme and Department of Microbiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China; Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom; Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Homo-oligomerization of the nucleoprotein (NP) of influenza A virus is crucial in providing a major structural framework for the assembly of viral ribonucleoprotein particles (RNPs). The nucleoprotein is also essential for transcription and replication during the virus life cycle. In the H5N1 NP structure, the tail loop region is important for NP to form oligomers. Here, by RNP reconstitution assay, we identified eight NP mutants which had different degrees of defect in forming functional RNPs, with the RNP activity of four mutants totally abolished (E339A; V408S,P410S; R416A; L418S,P419S) and the other four more than 50% decreased (R267A; I406S, R422A; E449A). Further characterization by static light scattering showed that the totally defective protein variants existed as monomers in vitro, deviating from the trimeric/oligomeric form of the wild-type NP. I406S, R422A and E449A existed as a mixture of unstable oligomers, thus resulting in reduction of RNP activity. Though R267A existed as monomer in vitro, it resumed oligomeric form upon RNA addition, and retained a certain degree of RNP activity. Our data suggests three factors which govern the NP oligomerization event: (1) interaction between the tail loop and the insertion groove; (2) maintenance of the tail loop conformation; and (3) stabilization of NP homo-oligomer. The work presented here provides information for the design of NP inhibitors for combating influenza virus infection.
PMID: 20463064 [PubMed - as supplied by publisher]
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J Virol. 2010 May 12. [Epub ahead of print]
Functional analysis of influenza H5N1 nucleoprotein tail loop reveals amino acids that are crucial for oligomerization and ribonucleoprotein activities.
Chan WH, Ng AK, Robb NC, Lam MK, Chan PK, Au SW, Wang JH, Fodor E, Shaw PC. - Department of Biochemistry and Centre for Protein Science and Crystallography, Molecular Biotechnology Programme and Department of Microbiology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China; Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, United Kingdom; Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
Homo-oligomerization of the nucleoprotein (NP) of influenza A virus is crucial in providing a major structural framework for the assembly of viral ribonucleoprotein particles (RNPs). The nucleoprotein is also essential for transcription and replication during the virus life cycle. In the H5N1 NP structure, the tail loop region is important for NP to form oligomers. Here, by RNP reconstitution assay, we identified eight NP mutants which had different degrees of defect in forming functional RNPs, with the RNP activity of four mutants totally abolished (E339A; V408S,P410S; R416A; L418S,P419S) and the other four more than 50% decreased (R267A; I406S, R422A; E449A). Further characterization by static light scattering showed that the totally defective protein variants existed as monomers in vitro, deviating from the trimeric/oligomeric form of the wild-type NP. I406S, R422A and E449A existed as a mixture of unstable oligomers, thus resulting in reduction of RNP activity. Though R267A existed as monomer in vitro, it resumed oligomeric form upon RNA addition, and retained a certain degree of RNP activity. Our data suggests three factors which govern the NP oligomerization event: (1) interaction between the tail loop and the insertion groove; (2) maintenance of the tail loop conformation; and (3) stabilization of NP homo-oligomer. The work presented here provides information for the design of NP inhibitors for combating influenza virus infection.
PMID: 20463064 [PubMed - as supplied by publisher]
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