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Wralstad EC, Raines RT. Sensitive detection of SARS-CoV-2 main protease 3CL pro with an engineered ribonuclease zymogen. Protein Sci 2024; 33:e4916. [PMID: 38501598 PMCID: PMC10949392 DOI: 10.1002/pro.4916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 01/13/2024] [Accepted: 01/17/2024] [Indexed: 03/20/2024]
Abstract
Alongside vaccines and antiviral therapeutics, diagnostic tools are a crucial aid in combating the COVID-19 pandemic caused by the etiological agent SARS-CoV-2. All common assays for infection rely on the detection of viral sub-components, including structural proteins of the virion or fragments of the viral genome. Selective pressure imposed by human intervention of COVID-19 can, however, induce viral mutations that decrease the sensitivity of diagnostic assays based on biomolecular structure, leading to an increase in false-negative results. In comparison, mutations are unlikely to alter the function of viral proteins, and viral machinery is under less selective pressure from vaccines and therapeutics. Accordingly, diagnostic assays that rely on biomolecular function can be more robust than ones that rely on biopolymer structure. Toward this end, we used a split intein to create a circular ribonuclease zymogen that is activated by the SARS-CoV-2 main protease, 3CLpro . Zymogen activation by 3CLpro leads to a >300-fold increase in ribonucleolytic activity, which can be detected with a highly sensitive fluorogenic substrate. This coupled assay can detect low nanomolar concentrations of 3CLpro within a timeframe comparable to that of common antigen-detection protocols. More generally, the concept of detecting a protease by activating a ribonuclease could be the basis of diagnostic tools for other indications.
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Affiliation(s)
- Evans C. Wralstad
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Ronald T. Raines
- Department of ChemistryMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
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Narayanan C, Gagné D, Reynolds KA, Doucet N. Conserved amino acid networks modulate discrete functional properties in an enzyme superfamily. Sci Rep 2017; 7:3207. [PMID: 28600532 PMCID: PMC5466627 DOI: 10.1038/s41598-017-03298-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/25/2017] [Indexed: 11/10/2022] Open
Abstract
In this work, we applied the sequence-based statistical coupling analysis approach to characterize conserved amino acid networks important for biochemical function in the pancreatic-type ribonuclease (ptRNase) superfamily. This superfamily-wide analysis indicates a decomposition of the RNase tertiary structure into spatially distributed yet physically connected networks of co-evolving amino acids, termed sectors. Comparison of this statistics-based description with new NMR experiments data shows that discrete amino acid networks, termed sectors, control the tuning of distinct functional properties in different enzyme homologs. Further, experimental characterization of evolutionarily distant sequences reveals that sequence variation at sector positions can distinguish homologs with a conserved dynamic pattern and optimal catalytic activity from those with altered dynamics and diminished catalytic activities. Taken together, these results provide important insights into the mechanistic design of the ptRNase superfamily, and presents a structural basis for evolutionary tuning of function in functionally diverse enzyme homologs.
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Affiliation(s)
- Chitra Narayanan
- INRS - Institut Armand Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada
| | - Donald Gagné
- INRS - Institut Armand Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada.,Structural Biology Initiative, CUNY Advanced Science Research Center, New York, NY, USA
| | - Kimberly A Reynolds
- Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Nicolas Doucet
- INRS - Institut Armand Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, QC, H7V 1B7, Canada. .,PROTEO, the Québec Network for Research on Protein Function, Engineering, and Applications, 1045 Avenue de la Médecine, Université Laval, Québec, QC, G1V 0A6, Canada. .,GRASP, the Groupe de Recherche Axé sur la Structure des Protéines, 3649 Promenade Sir William Osler, McGill University, Montréal, QC, H3G 0B1, Canada.
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Sacquin-Mora S. Fold and flexibility: what can proteins' mechanical properties tell us about their folding nucleus? J R Soc Interface 2016; 12:rsif.2015.0876. [PMID: 26577596 DOI: 10.1098/rsif.2015.0876] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The determination of a protein's folding nucleus, i.e. a set of native contacts playing an important role during its folding process, remains an elusive yet essential problem in biochemistry. In this work, we investigate the mechanical properties of 70 protein structures belonging to 14 protein families presenting various folds using coarse-grain Brownian dynamics simulations. The resulting rigidity profiles combined with multiple sequence alignments show that a limited set of rigid residues, which we call the consensus nucleus, occupy conserved positions along the protein sequence. These residues' side chains form a tight interaction network within the protein's core, thus making our consensus nuclei potential folding nuclei. A review of experimental and theoretical literature shows that most (above 80%) of these residues were indeed identified as folding nucleus member in earlier studies.
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Affiliation(s)
- Sophie Sacquin-Mora
- Laboratoire de Biochimie Théorique, CNRS UPR9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
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Gagné D, Charest LA, Morin S, Kovrigin EL, Doucet N. Conservation of flexible residue clusters among structural and functional enzyme homologues. J Biol Chem 2012; 287:44289-300. [PMID: 23135272 DOI: 10.1074/jbc.m112.394866] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Conformational flexibility between structural ensembles is an essential component of enzyme function. Although the broad dynamical landscape of proteins is known to promote a number of functional events on multiple time scales, it is yet unknown whether structural and functional enzyme homologues rely on the same concerted residue motions to perform their catalytic function. It is hypothesized that networks of contiguous and flexible residue motions occurring on the biologically relevant millisecond time scale evolved to promote and/or preserve optimal enzyme catalysis. In this study, we use a combination of NMR relaxation dispersion, model-free analysis, and ligand titration experiments to successfully capture and compare the role of conformational flexibility between two structural homologues of the pancreatic ribonuclease family: RNase A and eosinophil cationic protein (or RNase 3). In addition to conserving the same catalytic residues and structural fold, both homologues show similar yet functionally distinct clusters of millisecond dynamics, suggesting that conformational flexibility can be conserved among analogous protein folds displaying low sequence identity. Our work shows that the reduced conformational flexibility of eosinophil cationic protein can be dynamically and functionally reproduced in the RNase A scaffold upon creation of a chimeric hybrid between the two proteins. These results support the hypothesis that conformational flexibility is partly required for catalytic function in homologous enzyme folds, further highlighting the importance of dynamic residue sectors in the structural organization of proteins.
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Affiliation(s)
- Donald Gagné
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Université du Québec, Laval, Quebec H7V 1B7, Canada
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