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McPartlin DA, Murphy C, Fitzgerald J, Ma H, Regan F, O'Kennedy RJ. Understanding microcystin-LR antibody binding interactions using in silico docking and in vitro mutagenesis. Protein Eng Des Sel 2019; 32:533-542. [PMID: 32725153 DOI: 10.1093/protein/gzaa016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 11/13/2022] Open
Abstract
Microcystins (MCs) are a group of highly potent cyanotoxins that are becoming more widely distributed due to increased global temperatures and climate change. Microcystin-leucine-arginine (MC-LR) is the most potent and most common variant, with a guideline limit of 1 μg/l in drinking water. We previously developed a novel avian single-chain fragment variable (scFv), designated 2G1, for use in an optical-planar waveguide detection system for microcystin determination. This current work investigates interactions between 2G1 and MC-LR at the molecular level through modelling with an avian antibody template and molecular docking by AutoDock Vina to identify key amino acid (AA) residues involved. These potential AA interactions were investigated in vitro by targeted mutagenesis, specifically, by alanine scanning mutations. Glutamic acid (E) was found to play a critical role in the 2G1-MC-LR binding interaction, with the heavy chain glutamic acid (E) 102 (H-E102) forming direct bonds with the arginine (R) residue of MC-LR. In addition, alanine mutation of light chain residue aspartic acid 57 (L-D57) led to an improvement in antigen-binding observed using enzyme-linked immunosorbent assay (ELISA), and was confirmed by surface plasmon resonance (SPR). This work will contribute to improving the binding of recombinant anti-MC-LR to its antigen and aid in the development of a higher sensitivity harmful algal toxin diagnostic.
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Affiliation(s)
| | - Caroline Murphy
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Jenny Fitzgerald
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Hui Ma
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Fiona Regan
- Water Institute, Dublin City University, Dublin 9, Ireland
| | - Richard J O'Kennedy
- School of Biotechnology, Dublin City University, Dublin 9, Ireland.,Research, Development and Innovation, Qatar Foundation and Hamad Bin Khalifa University, Doha, Qatar
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McPartlin DA, Loftus JH, Crawley AS, Silke J, Murphy CS, O'Kennedy RJ. Biosensors for the monitoring of harmful algal blooms. Curr Opin Biotechnol 2017; 45:164-169. [PMID: 28427011 DOI: 10.1016/j.copbio.2017.02.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/17/2017] [Accepted: 02/28/2017] [Indexed: 12/11/2022]
Abstract
Harmful algal blooms (HABs) are a major global concern due to their propensity to cause environmental damage, healthcare issues and economic losses. In particular, the presence of toxic phytoplankton is a cause for concern. Current HAB monitoring programs often involve laborious laboratory-based analysis at a high cost and with long turnaround times. The latter also hampers the potential to develop accurate and reliable models that can predict HAB occurrence. However, a promising solution for this issue may be in the form of remotely deployed biosensors, which can rapidly and continuously measure algal and toxin levels at the point-of-need (PON), at a low cost. This review summarises the issues HABs present, how they are difficult to monitor and recently developed biosensors that may improve HAB-monitoring challenges.
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Affiliation(s)
| | | | - Aoife S Crawley
- School of Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Joe Silke
- Marine Institute, Rinville, Oranmore, Co. Galway, Ireland
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Murphy C, Stack E, Krivelo S, McPartlin DA, Byrne B, Greef C, Lochhead MJ, Husar G, Devlin S, Elliott CT, O'Kennedy RJ. Detection of the cyanobacterial toxin, microcystin-LR, using a novel recombinant antibody-based optical-planar waveguide platform. Biosens Bioelectron 2014; 67:708-14. [PMID: 25459059 DOI: 10.1016/j.bios.2014.10.039] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 10/02/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
Abstract
Microcystins are a major group of cyanobacterial heptapeptide toxins found in freshwater and brackish environments. There is currently an urgent requirement for highly-sensitive, rapid and in-expensive detection methodologies for these toxins. A novel single chain fragment variable (scFv) fragment was generated and is the first known report of a recombinant anti-microcystin avian antibody. In a surface plasmon resonance-based immunoassay, the antibody fragment displayed cross-reactivity with seven microcystin congeners (microcystin-leucine-arginine (MC-LR) 100%, microcystin-tyrosine-arginine (MC-YR) 79.7%, microcystin-leucine-alanine (MC-LA) 74.8%, microcystin-leucine-phenylalanine (MC-LF) 67.5%, microcystin-leucine-tryptophan (MC-LW) 63.7%, microcystin-arginine-arginine (MC-RR) 60.1% and nodularin (Nod) 69.3%, % cross reactivity). Following directed molecular evolution of the parental clone the resultant affinity-enhanced antibody fragment was applied in an optimized fluorescence immunoassay on a planar waveguide detection system. This novel immuno-sensing format can detect free microcystin-LR with a functional limit of detection of 0.19 ng mL(-1)and a detection range of 0.21-5.9 ng mL(-1). The assay is highly reproducible (displaying percentage coefficients of variance below 8% for intra-day assays and below 11% for inter-day assays), utilizes an inexpensive cartridge system with low reagent volumes and can be completed in less than twenty minutes.
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Affiliation(s)
- Caroline Murphy
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland.
| | - Edwina Stack
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland
| | - Svetlana Krivelo
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland
| | - Daniel A McPartlin
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland
| | - Barry Byrne
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland
| | | | | | - Greg Husar
- MBio Diagnostics Inc., Boulder, CO, 80301, USA
| | - Shauna Devlin
- Institute for Global Food Security (IGFS), School of Biological Sciences, Queen's University, Malone Road, 18-30 Belfast, BT9 5BN, Northern Ireland, United Kingdom
| | - Christopher T Elliott
- Institute for Global Food Security (IGFS), School of Biological Sciences, Queen's University, Malone Road, 18-30 Belfast, BT9 5BN, Northern Ireland, United Kingdom
| | - Richard J O'Kennedy
- School of Biotechnology, National Centre for Sensor Research and Biomedical Diagnostics Institute, Dublin City University, Dublin 9, Ireland
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McPartlin DA, O'Kennedy RJ. Point-of-care diagnostics, a major opportunity for change in traditional diagnostic approaches: potential and limitations. Expert Rev Mol Diagn 2014; 14:979-98. [PMID: 25300742 DOI: 10.1586/14737159.2014.960516] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
'Point-of-care' (POC) diagnostics are a powerful emerging healthcare approach. They can rapidly provide statistically significant results, are simple to use, do not require specialized equipment and are cost-effective. For these reasons, they have the potential to play a major role in revolutionizing the diagnosis, initiation and monitoring of treatment of major global diseases. This review focuses on antibody-based POC devices that target four major global diseases: cardiovascular diseases, prostate cancer, HIV infection and tuberculosis. The key statistics and pathology of each disease is described in detail, followed by an in-depth discussion on emerging POC devices that target each disease, highlighting their potential and limitations.
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Affiliation(s)
- Daniel A McPartlin
- School of Biotechnology, Dublin City University, Glasnevin, Dublin 9, Co. Dublin, Ireland
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