This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow E-mail this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Assenberg, R.
Right arrow Articles by Mancini, E. J.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Assenberg, R.
Right arrow Articles by Mancini, E. J.

 Previous Article  |  Next Article 

Journal of Virology, December 2009, p. 12895-12906, Vol. 83, No. 24
0022-538X/09/$08.00+0     doi:10.1128/JVI.00942-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Crystal Structure of a Novel Conformational State of the Flavivirus NS3 Protein: Implications for Polyprotein Processing and Viral Replication{triangledown}

René Assenberg,1 Eloise Mastrangelo,2,3 Thomas S. Walter,1 Anil Verma,1 Mario Milani,2,3 Raymond J. Owens,1 David I. Stuart,1 Jonathan M. Grimes,1 and Erika J. Mancini1*

Division of Structural Biology and Oxford Protein Production Facility, Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, United Kingdom,1 Department of Biomolecular Sciences and Biotechnology, University of Milano, I-20133 Milano, Italy,2 CNR-INFM S3, National Research Center on Nanostructure and BioSystems at Surfaces, 41100 Modena, Italy3

Received 12 May 2009/ Accepted 22 September 2009

The flavivirus genome comprises a single strand of positive-sense RNA, which is translated into a polyprotein and cleaved by a combination of viral and host proteases to yield functional proteins. One of these, nonstructural protein 3 (NS3), is an enzyme with both serine protease and NTPase/helicase activities. NS3 plays a central role in the flavivirus life cycle: the NS3 N-terminal serine protease together with its essential cofactor NS2B is involved in the processing of the polyprotein, whereas the NS3 C-terminal NTPase/helicase is responsible for ATP-dependent RNA strand separation during replication. An unresolved question remains regarding why NS3 appears to encode two apparently disconnected functionalities within one protein. Here we report the 2.75-Å-resolution crystal structure of full-length Murray Valley encephalitis virus NS3 fused with the protease activation peptide of NS2B. The biochemical characterization of this construct suggests that the protease has little influence on the helicase activity and vice versa. This finding is in agreement with the structural data, revealing a single protein with two essentially segregated globular domains. Comparison of the structure with that of dengue virus type 4 NS2B-NS3 reveals a relative orientation of the two domains that is radically different between the two structures. Our analysis suggests that the relative domain-domain orientation in NS3 is highly variable and dictated by a flexible interdomain linker. The possible implications of this conformational flexibility for the function of NS3 are discussed.

* Corresponding author. Mailing address: Division of Structural Biology, the Henry Wellcome Building for Genomic Medicine, Oxford University, Roosevelt Drive, Oxford OX3 7BN, United Kingdom. Phone: 44 1865 287560. Fax: 44 1865 56 287547. E-mail: erika{at}strubi.ox.ac.uk

{triangledown} Published ahead of print on 30 September 2009.

Journal of Virology, December 2009, p. 12895-12906, Vol. 83, No. 24
0022-538X/09/$08.00+0     doi:10.1128/JVI.00942-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2010 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»