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Guerrero-Rubio MA, Walker-Hale N, Guo R, Sheehan H, Timoneda A, Gandia-Herrero F, Brockington SF. Are seven amino acid substitutions sufficient to explain the evolution of high l-DOPA 4,5-dioxygenase activity leading to betalain pigmentation? Revisiting the gain-of-function mutants of Bean et al. (2018). THE NEW PHYTOLOGIST 2023; 239:2265-2276. [PMID: 37243529 DOI: 10.1111/nph.18981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/27/2023] [Indexed: 05/29/2023]
Abstract
This work revisits a publication by Bean et al. (2018) that reports seven amino acid substitutions are essential for the evolution of l-DOPA 4,5-dioxygenase (DODA) activity in Caryophyllales. In this study, we explore several concerns which led us to replicate the analyses of Bean et al. (2018). Our comparative analyses, with structural modelling, implicate numerous residues additional to those identified by Bean et al. (2018), with many of these additional residues occurring around the active site of BvDODAα1. We therefore replicated the analyses of Bean et al. (2018) to re-observe the effect of their original seven residue substitutions in a BvDODAα2 background, that is the BvDODAα2-mut3 variant. Multiple in vivo assays, in both Saccharomyces cerevisiae and Nicotiana benthamiana, did not result in visible DODA activity in BvDODAα2-mut3, with betalain production always 10-fold below BvDODAα1. In vitro assays also revealed substantial differences in both catalytic activity and pH optima between BvDODAα1, BvDODAα2 and BvDODAα2-mut3 proteins, explaining their differing performance in vivo. In summary, we were unable to replicate the in vivo analyses of Bean et al. (2018), and our quantitative in vivo and in vitro analyses suggest a minimal effect of these seven residues in altering catalytic activity of BvDODAα2. We conclude that the evolutionary pathway to high DODA activity is substantially more complex than implied by Bean et al. (2018).
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Affiliation(s)
| | - Nathanael Walker-Hale
- Department of Plant Sciences, University of Cambridge, Tennis Court Road, CB2 3EA, Cambridge, UK
| | - Rui Guo
- Department of Plant Sciences, University of Cambridge, Tennis Court Road, CB2 3EA, Cambridge, UK
| | - Hester Sheehan
- Department of Plant Sciences, University of Cambridge, Tennis Court Road, CB2 3EA, Cambridge, UK
| | - Alfonso Timoneda
- Department of Plant Sciences, University of Cambridge, Tennis Court Road, CB2 3EA, Cambridge, UK
| | - Fernando Gandia-Herrero
- Departamento de Bioquímica y Biología Molecular A, Unidad Docente de Biología, Facultad de Veterinaria, Regional Campus of International Excellence 'Campus Mare Nostrum', Universidad de Murcia, 30100, Murcia, Spain
| | - Samuel F Brockington
- Department of Plant Sciences, University of Cambridge, Tennis Court Road, CB2 3EA, Cambridge, UK
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Bioactive potential and spectroscopical characterization of a novel family of plant pigments betalains derived from dopamine. Food Res Int 2022; 162:111956. [DOI: 10.1016/j.foodres.2022.111956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/28/2022] [Accepted: 09/16/2022] [Indexed: 11/23/2022]
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