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Keenan T, Spears RJ, Akkad S, Mahon CS, Hatton NE, Walton J, Noble A, Yates ND, Baumann CG, Parkin A, Signoret N, Fascione MA. A Tale of Two Bioconjugations: pH Controlled Divergent Reactivity of Protein α-oxo-Aldehydes in Competing α-oxo-Mannich and Catalyst-Free Aldol Ligations. ACS Chem Biol 2021; 16:2387-2400. [PMID: 34751550 DOI: 10.1021/acschembio.1c00531] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Site-selective chemical methods for protein bioconjugation have revolutionized the fields of cell and chemical biology through the development of novel protein/enzyme probes bearing fluorescent, spectroscopic, or even toxic cargos. Herein, we report two new methods for the bioconjugation of α-oxo aldehyde handles within proteins using small molecule aniline and/or phenol probes. The "α-oxo-Mannich" and "catalyst-free aldol" ligations both compete for the electrophilic α-oxo aldehyde, which displays pH divergent reactivity proceeding through the "Mannich" pathway at acidic pH to afford bifunctionalized bioconjugates, and the "catalyst-free aldol" pathway at neutral pH to afford monofunctionalized bioconjugates. We explore the substrate scope and utility of both of these bioconjugations in the construction of neoglycoproteins, in the process formulating a mechanistic rationale for how both pathways intersect with each other at different reaction pH's.
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Affiliation(s)
- Tessa Keenan
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Richard J. Spears
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Saeed Akkad
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Clare S. Mahon
- Department of Chemistry, Durham University, Durham, United Kingdom DH1 3LE
| | - Natasha E. Hatton
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Julia Walton
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Amanda Noble
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Nicholas D. Yates
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | | | - Alison Parkin
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
| | - Nathalie Signoret
- Hull York Medical School, University of York, York, United Kingdom YO10 5DD
| | - Martin A. Fascione
- Department of Chemistry, University of York, York, United Kingdom YO10 5DD
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Yates ND, Dowsett MR, Bentley P, Dickenson-Fogg JA, Pratt A, Blanford CF, Fascione MA, Parkin A. Aldehyde-Mediated Protein-to-Surface Tethering via Controlled Diazonium Electrode Functionalization Using Protected Hydroxylamines. Langmuir 2020; 36:5654-5664. [PMID: 31721585 DOI: 10.1021/acs.langmuir.9b01254] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report a diazonium electro-grafting method for the covalent modification of conducting surfaces with aldehyde-reactive hydroxylamine functionalities that facilitate the wiring of redox-active (bio)molecules to electrode surfaces. Hydroxylamine near-monolayer formation is achieved via a phthalimide-protection and hydrazine-deprotection strategy that overcomes the multilayer formation that typically complicates diazonium surface modification. This surface modification strategy is characterized using electrochemistry (electrochemical impedance spectroscopy and cyclic voltammetry), X-ray photoelectron spectroscopy, and quartz crystal microbalance with dissipation monitoring. Thus-modified glassy carbon, boron-doped diamond, and gold surfaces are all shown to ligate to small molecule aldehydes, yielding surface coverages of 150-170, 40, and 100 pmol cm-2, respectively. Bioconjugation is demonstrated via the coupling of a dilute (50 μM) solution of periodate-oxidized horseradish peroxidase enzyme to a functionalized gold surface under biocompatible conditions (H2O solvent, pH 4.5, 25 °C).
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Affiliation(s)
- Nicholas D Yates
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Mark R Dowsett
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Phillip Bentley
- Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Jack A Dickenson-Fogg
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Andrew Pratt
- Department of Physics, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Christopher F Blanford
- School of Materials, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester, M1 7DN, United Kingdom
| | - Martin A Fascione
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
| | - Alison Parkin
- Department of Chemistry, University of York, Heslington, York, YO10 5DD, United Kingdom
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A. Joule J, A. Peters D, D. Yates N, I. C. Scopes D. Synthesis of 5,7,8,9,10,11-Hexahydro-7-oxo-8,11-iminoazepino[1,2-b]isoquinolines. HETEROCYCLES 1995. [DOI: 10.3987/com-94-s99] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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