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Gaule TG, Smith MA, Tych KM, Pirrat P, Trinh CH, Pearson AR, Knowles PF, McPherson MJ. Oxygen Activation Switch in the Copper Amine Oxidase of Escherichia coli. Biochemistry 2018; 57:5301-5314. [PMID: 30110143 PMCID: PMC6136094 DOI: 10.1021/acs.biochem.8b00633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Copper amine oxidases (CuAOs) are metalloenzymes that reduce molecular oxygen to hydrogen peroxide during catalytic turnover of primary amines. In addition to Cu2+ in the active site, two peripheral calcium sites, ∼32 Å from the active site, have roles in Escherichia coli amine oxidase (ECAO). The buried Ca2+ (Asp533, Leu534, Asp535, Asp678, and Ala679) is essential for full-length protein production, while the surface Ca2+ (Glu573, Tyr667, Asp670, and Glu672) modulates biogenesis of the 2,4,5-trihydroxyphenylalanine quinone (TPQ) cofactor. The E573Q mutation at the surface site prevents calcium binding and TPQ biogenesis. However, TPQ biogenesis can be restored by a suppressor mutation (I342F) in the proposed oxygen delivery channel to the active site. While supporting TPQ biogenesis (∼60% WTECAO TPQ), I342F/E573Q has almost no amine oxidase activity (∼4.6% WTECAO activity). To understand how these long-range mutations have major effects on TPQ biogenesis and catalysis, we employed ultraviolet-visible spectroscopy, steady-state kinetics, inhibition assays, and X-ray crystallography. We show that the surface metal site controls the equilibrium (disproportionation) of the Cu2+-substrate reduced TPQ (TPQAMQ) Cu+-TPQ semiquinone (TPQSQ) couple. Removal of the calcium ion from this site by chelation or mutagenesis shifts the equilibrium to Cu2+-TPQAMQ or destabilizes Cu+-TPQSQ. Crystal structure analysis shows that TPQ biogenesis is stalled at deprotonation in the Cu2+-tyrosinate state. Our findings support WTECAO using the inner sphere electron transfer mechanism for oxygen reduction during catalysis, and while a Cu+-tyrosyl radical intermediate is not essential for TPQ biogenesis, it is required for efficient biogenesis.
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Affiliation(s)
- Thembaninkosi G Gaule
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
| | - Mark A Smith
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
| | - Katarzyna M Tych
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K.,Physik-Department, Lehrstuhl für Biophysik E22 , Technische Universität München , D-85748 Garching , Germany
| | - Pascale Pirrat
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
| | - Chi H Trinh
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
| | - Arwen R Pearson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K.,Hamburg Centre of Ultrafast Imaging and Institute for Nanostructure and Solid State Physics , Universität Hamburg , D-22761 Hamburg , Germany
| | - Peter F Knowles
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
| | - Michael J McPherson
- Astbury Centre for Structural Molecular Biology and School of Molecular and Cellular Biology, Faculty of Biological Sciences , University of Leeds , Leeds LS2 9JT , U.K
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Solomon EI, Heppner DE, Johnston EM, Ginsbach JW, Cirera J, Qayyum M, Kieber-Emmons MT, Kjaergaard CH, Hadt RG, Tian L. Copper active sites in biology. Chem Rev 2014; 114:3659-853. [PMID: 24588098 PMCID: PMC4040215 DOI: 10.1021/cr400327t] [Citation(s) in RCA: 1129] [Impact Index Per Article: 112.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
| | - David E. Heppner
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | - Jake W. Ginsbach
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Jordi Cirera
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Munzarin Qayyum
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | | | | | - Ryan G. Hadt
- Department of Chemistry, Stanford University, Stanford, CA, 94305
| | - Li Tian
- Department of Chemistry, Stanford University, Stanford, CA, 94305
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The role of protein crystallography in defining the mechanisms of biogenesis and catalysis in copper amine oxidase. Int J Mol Sci 2012; 13:5375-5405. [PMID: 22754303 PMCID: PMC3382800 DOI: 10.3390/ijms13055375] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2012] [Revised: 04/22/2012] [Accepted: 04/26/2012] [Indexed: 12/22/2022] Open
Abstract
Copper amine oxidases (CAOs) are a ubiquitous group of enzymes that catalyze the conversion of primary amines to aldehydes coupled to the reduction of O2 to H2O2. These enzymes utilize a wide range of substrates from methylamine to polypeptides. Changes in CAO activity are correlated with a variety of human diseases, including diabetes mellitus, Alzheimer’s disease, and inflammatory disorders. CAOs contain a cofactor, 2,4,5-trihydroxyphenylalanine quinone (TPQ), that is required for catalytic activity and synthesized through the post-translational modification of a tyrosine residue within the CAO polypeptide. TPQ generation is a self-processing event only requiring the addition of oxygen and Cu(II) to the apoCAO. Thus, the CAO active site supports two very different reactions: TPQ synthesis, and the two electron oxidation of primary amines. Crystal structures are available from bacterial through to human sources, and have given insight into substrate preference, stereospecificity, and structural changes during biogenesis and catalysis. In particular both these processes have been studied in crystallo through the addition of native substrates. These latter studies enable intermediates during physiological turnover to be directly visualized, and demonstrate the power of this relatively recent development in protein crystallography.
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