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Context-Dependent Cleavage of the Capsid Protein by the West Nile Virus Protease Modulates the Efficiency of Virus Assembly. J Virol 2015; 89:8632-42. [PMID: 26063422 DOI: 10.1128/jvi.01253-15] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 06/02/2015] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED The molecular mechanisms that define the specificity of flavivirus RNA encapsulation are poorly understood. Virions composed of the structural proteins of one flavivirus and the genomic RNA of a heterologous strain can be assembled and have been developed as live attenuated vaccine candidates for several flaviviruses. In this study, we discovered that not all combinations of flavivirus components are possible. While a West Nile virus (WNV) subgenomic RNA could readily be packaged by structural proteins of the DENV2 strain 16681, production of infectious virions with DENV2 strain New Guinea C (NGC) structural proteins was not possible, despite the very high amino acid identity between these viruses. Mutagenesis studies identified a single residue (position 101) of the DENV capsid (C) protein as the determinant for heterologous virus production. C101 is located at the P1' position of the NS2B/3 protease cleavage site at the carboxy terminus of the C protein. WNV NS2B/3 cleavage of the DENV structural polyprotein was possible when a threonine (Thr101 in strain 16681) but not a serine (Ser101 in strain NGC) occupied the P1' position, a finding not predicted by in vitro protease specificity studies. Critically, both serine and threonine were tolerated at the P1' position of WNV capsid. More extensive mutagenesis revealed the importance of flanking residues within the polyprotein in defining the cleavage specificity of the WNV protease. A more detailed understanding of the context dependence of viral protease specificity may aid the development of new protease inhibitors and provide insight into associated patterns of drug resistance. IMPORTANCE West Nile virus (WNV) and dengue virus (DENV) are mosquito-borne flaviviruses that cause considerable morbidity and mortality in humans. No specific antiflavivirus therapeutics are available for treatment of infection. Proteolytic processing of the flavivirus polyprotein is an essential step in the replication cycle and is an attractive target for antiviral development. The design of protease inhibitors has been informed by insights into the molecular details of the interactions of proteases and their substrates. In this article, studies of the processing of WNV and DENV capsid proteins by the WNV protease identified an unexpected contribution of the sequence surrounding critical residues within the cleavage site on protease specificity. This demonstration of context-dependent protease cleavage has implications for the design of chimeric flaviviruses, new therapeutics, and the interpretation of flavivirus protease substrate specificity studies.
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Corrie SR, Feng Q, Blair T, Hawes SE, Kiviat NB, Trau M. Multiplatform comparison of multiplexed bead arrays using HPV genotyping as a test case. Cytometry A 2011; 79:713-9. [DOI: 10.1002/cyto.a.21109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 05/08/2011] [Accepted: 06/24/2011] [Indexed: 12/27/2022]
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Kozak D, Kithva P, Bax J, Surawski PPT, Monteiro MJ, Trau M. Development of encoded particle-polymer arrays for the accelerated screening of antifouling layers. Chem Commun (Camb) 2011; 47:9687-9. [PMID: 21773613 DOI: 10.1039/c1cc13571f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A multiplexed screening methodology for the rapid development of antifouling polymer surfaces is presented. An array of protein resistant polymer layers with high grafting (>100 mg m(-2)) were polymerized on optically encoded particles. Multiplexed analysis showed a 97% reduction in nonspecific protein adsorption for all polymer layers created.
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Affiliation(s)
- Darby Kozak
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane, Australia 4072.
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Strategies for development of dengue virus inhibitors. Antiviral Res 2010; 85:450-62. [DOI: 10.1016/j.antiviral.2009.12.011] [Citation(s) in RCA: 211] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 12/16/2009] [Accepted: 12/30/2009] [Indexed: 01/03/2023]
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Chen A, Kozak D, Battersby BJ, Forrest RM, Scholler N, Urban N, Trau M. Antifouling surface layers for improved signal-to-noise of particle-based immunoassays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13510-5. [PMID: 19928944 PMCID: PMC2891774 DOI: 10.1021/la903148n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A 10-fold improvement in the signal-to-noise (S/N) ratio of an optically encoded silica particle-based immunoassay was achieved through incorporating a protein resistant poly(ethylene glycol) (PEG) surface layer and optimizing antibody immobilization conditions. PEG was activated using 2,2,2-trifluoroethanesulfonyl chloride (tresyl) and required a minimum reaction time of 1.5 h. The activated PEG had a reactive half-life of approximately 5 h when stored in acidified dimethyl sulfoxide (DMSO). By increasing the protein incubation time and concentration, a maximum antibody loading on the particle surface of 1.6 x 10(-2) molecules per nm(2) was achieved. The assay S/N ratio was assessed using a multiplexed multicomponent optically encoded species-specific immunoassay. Encoded particles were covalently grafted or nonspecifically coated with either bovine or mouse IgG for the simultaneous detection of complementary anti-IgG "target" or uncomplementary anti-IgG "noise". The versatility and potential as a serum-based assay platform was demonstrated by immobilizing either a polyclonal antibody or an engineered single-chain variable fragment (scFv) capture probe on particles for the detection of the ovarian cancer biomarker, mesothelin (MSLN). The MLSN antigen was spiked into PBS buffer or 50% human serum. Both capture probe orientations, and media conditions showed similar low level detection limits of 5 ng/mL; however, a 40% decrease in maximum signal intensity was observed for assays run in 50% serum.
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Affiliation(s)
- Annie Chen
- Biomarker Research and Development Centre, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Darby Kozak
- Biomarker Research and Development Centre, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Bronwyn J. Battersby
- Biomarker Research and Development Centre, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Robin M. Forrest
- Translational and Outcomes Research Group, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Nathalie Scholler
- Ovarian Cancer Research Center, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
| | - Nicole Urban
- Translational and Outcomes Research Group, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Matt Trau
- Biomarker Research and Development Centre, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
- Telephone: +61 7 334 64173 Fax: +61 7 334 63973
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Marcon L, Battersby BJ, Rühmann A, Ford K, Daley M, Lawrie GA, Trau M. 'On-the-fly' optical encoding of combinatorial peptide libraries for profiling of protease specificity. MOLECULAR BIOSYSTEMS 2009; 6:225-33. [PMID: 20024084 DOI: 10.1039/b909087h] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Large solid-phase combinatorial libraries currently play an important role in areas such as infectious disease biomarker discovery, profiling of protease specificity and anticancer drug discovery. Because compounds on solid support beads are not positionally-encoded as they are in microarrays, innovative methods of encoding are required. There are many advantages associated with optical encoding and several strategies have been described in the literature to combine fluorescence encoding methods with solid-phase library synthesis. We have previously introduced an alternative fluorescence-based encoding method ("colloidal barcoding"), which involves encoding 10-20 mum support beads during a split-and-mix synthesis with smaller 0.6-0.8 mum silica colloids that contain specific and identifiable combinations of fluorescent dye. The power of this 'on-the-fly' encoding approach lies in the efficient use of a small number of fluorescent dyes to encode millions of compounds. Described herein, for the first time, is the use of a colloid-barcoded library in a biological assay (i.e., protease profiling) combined with the use of confocal microscopy to decode the colloidal barcode. In this proof-of-concept demonstration, a small focussed peptide library was optically-encoded during a combinatorial synthesis, incubated with a protease (trypsin), analysed by flow cytometry and decoded via confocal microscopy. During assay development, a range of parameters were investigated and optimised, including substrate (or probe) loading, barcode stability, characteristics of the peptide-tagging fluorophore, and spacer group configuration. Through successful decoding of the colloidal barcodes, it was confirmed that specific peptide sequences presenting one or two cleavage sites were recognised by trypsin while peptide sequences not cleavable by trypsin remained intact.
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Affiliation(s)
- Lionel Marcon
- Centre for Biomarker Research and Development, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
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Marcon L, Spriet C, Meehan TD, Battersby BJ, Lawrie GA, Héliot L, Trau M. Synthesis and application of FRET nanoparticles in the profiling of a protease. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:2053-2056. [PMID: 19517488 DOI: 10.1002/smll.200801887] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Affiliation(s)
- Lionel Marcon
- Centre for Nanotechnology and Biomaterials, Australian Institute for Bioengineering and Nanotechnology, University of Queensland, QLD, Australia
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Kozak D, Surawski P, Thoren KM, Lu CY, Marcon L, Trau M. Improving the Signal-to-Noise Performance of Molecular Diagnostics with PEG-Lysine Copolymer Dendrons. Biomacromolecules 2009; 10:360-5. [DOI: 10.1021/bm8011314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Darby Kozak
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Peter Surawski
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Kurt M Thoren
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Chieh-Yu Lu
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Lionel Marcon
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
| | - Matt Trau
- Centre for Nanotechnology and Biomaterials, Level 5 East, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia, QLD 4072, Australia
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Surawski PPT, Battersby BJ, Vogel R, Lawrie G, Trau M. Modification and optimization of organosilica microspheres for peptide synthesis and microsphere-based immunoassays. MOLECULAR BIOSYSTEMS 2009; 5:826-31. [DOI: 10.1039/b817080k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wildeboer D, Jeganathan F, Price RG, Abuknesha RA. Characterization of bacterial proteases with a panel of fluorescent peptide substrates. Anal Biochem 2009; 384:321-8. [DOI: 10.1016/j.ab.2008.10.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 10/03/2008] [Accepted: 10/08/2008] [Indexed: 10/21/2022]
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