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Abstract
This first serious attempt at an autobiographical accounting has forced me to sit still long enough to compile my thoughts about a long personal and scientific journey. I especially hope that my trajectory will be of interest and perhaps beneficial to much younger women who are just getting started in their careers. To paraphrase from Virginia Woolf's writings in A Room of One's Own at the beginning of the 20th century, "for most of history Anonymous was a Woman." However, Ms. Woolf is also quoted as saying "nothing has really happened until it has been described," a harbinger of the enormous historical changes that were about to be enacted and recorded by women in the sciences and other disciplines. The progress in my chosen field of study-the chemical basis of enzyme action-has also been remarkable, from the first description of an enzyme's 3D structure to a growing and deep understanding of the origins of enzyme catalysis.
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Affiliation(s)
- Judith P Klinman
- Department of Chemistry, Department of Molecular and Cell Biology, and California Institute of Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, USA;
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2
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Shoji M, Murakawa T, Boero M, Shigeta Y, Hayashi H, Okajima T. Unique protonation states of aspartate and topaquinone in the active site of copper amine oxidase. RSC Adv 2020; 10:38631-38639. [PMID: 35517562 PMCID: PMC9057271 DOI: 10.1039/d0ra06365g] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/13/2020] [Indexed: 01/31/2023] Open
Abstract
The oxidative deamination of biogenic amines, crucial in the metabolism of a wealth of living organisms, is catalyzed by copper amine oxidases (CAOs). In this work, on the ground of accurate molecular modeling, we provide a clear insight into the unique protonation states of the key catalytic aspartate residue Asp298 and the prosthetic group of topaquinone (TPQ) in the CAO of Arthrobacter globiformis (AGAO). This provides both extensions and complementary information to the crystal structure determined by our recent neutron diffraction (ND) experiment. The hybrid quantum mechanics/molecular mechanics (QM/MM) simulations suggest that the ND structure closely resembles a state in which Asp298 is protonated and the TPQ takes an enolate form. The TPQ keto form can coexist in the fully protonated state. The energetic and structural analyses indicate that the active site structure of the AGAO crystal is not a single state but rather a mixture of the different protonation and conformational states identified in this work. Copper amine oxidases catalyze the oxidative deamination of biogenic amines. We investigated the unique protonation states in the active site using first-principle calculations.![]()
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Affiliation(s)
- Mitsuo Shoji
- Center for Computational Sciences
- University of Tsukuba
- Tsukuba
- Japan
- JST-PRESTO
| | | | - Mauro Boero
- University of Strasbourg
- Institut de Physique et Chimie des Matériaux de Strasbourg
- CNRS
- UMR 7504
- France
| | - Yasuteru Shigeta
- Center for Computational Sciences
- University of Tsukuba
- Tsukuba
- Japan
| | | | - Toshihide Okajima
- Department of Chemistry
- Osaka Medical College
- Takatsuki
- Japan
- Institute of Scientific and Industrial Research
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Ayikpoe RS, Latham JA. MftD Catalyzes the Formation of a Biologically Active Redox Center in the Biosynthesis of the Ribosomally Synthesized and Post-translationally Modified Redox Cofactor Mycofactocin. J Am Chem Soc 2019; 141:13582-13591. [PMID: 31381312 DOI: 10.1021/jacs.9b06102] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mycofactocin (MFT) is a putative ribosomally synthesized and post-translationally modified (RiPP) redox cofactor. The biosynthesis of MFT is encoded by the gene cluster mftABCDEF. While processing of the precursor peptide by MftB, MftC, and MftE has been shown to result in the formation of the small molecule 3-amino-5-[(p-hydroxyphenyl)methyl]-4,4-dimethyl-2-pyrrolidinone (AHDP), no activity has been shown for the putative dehydrogenase MftD and the putative glycosyltransferase MftF. In addition, evidence demonstrating that MFT is a redox cofactor has only been limited to the requirement of mft genes for ethanol assimilation in Mycobacterium smegmatis mc2155. Here, we demonstrate that MftD catalyzes the oxidative deamination of AHDP, forming an α-keto moiety on the resulting molecule, which we call pre-mycofactocin (PMFT). We characterize PMFT by 1D and 2D NMR spectroscopy techniques and by high-resolution mass spectrometry data to solve its structure. We further characterized PMFT by cyclic voltammetry and found its midpoint potential to be ∼255 mV. Lastly, we demonstrate that PMFT is a biologically active redox cofactor that oxidizes NADH bound by M. smegmatis carveol dehydrogenase (MsCDH) and can be used by MsCDH in the oxidation of carveol. These data demonstrate for the first time that PMFT functions as a biologically active redox mediator and provides the most direct evidence to date that MFT is a RiPP-derived redox cofactor.
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Affiliation(s)
- Richard S Ayikpoe
- Department of Chemistry and Biochemistry , University of Denver , Denver , Colorado 80210 , United States
| | - John A Latham
- Department of Chemistry and Biochemistry , University of Denver , Denver , Colorado 80210 , United States
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4
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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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Houen G. Mammalian Cu-containing amine oxidases (CAOs): New methods of analysis, structural relationships, and possible functions. APMIS 2017; 107:5-46. [DOI: 10.1111/apm.1999.107.s96.5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Quist DA, Diaz DE, Liu JJ, Karlin KD. Activation of dioxygen by copper metalloproteins and insights from model complexes. J Biol Inorg Chem 2017; 22:253-288. [PMID: 27921179 PMCID: PMC5600896 DOI: 10.1007/s00775-016-1415-2] [Citation(s) in RCA: 163] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 11/11/2016] [Indexed: 02/08/2023]
Abstract
Nature uses dioxygen as a key oxidant in the transformation of biomolecules. Among the enzymes that are utilized for these reactions are copper-containing metalloenzymes, which are responsible for important biological functions such as the regulation of neurotransmitters, dioxygen transport, and cellular respiration. Enzymatic and model system studies work in tandem in order to gain an understanding of the fundamental reductive activation of dioxygen by copper complexes. This review covers the most recent advancements in the structures, spectroscopy, and reaction mechanisms for dioxygen-activating copper proteins and relevant synthetic models thereof. An emphasis has also been placed on cofactor biogenesis, a fundamentally important process whereby biomolecules are post-translationally modified by the pro-enzyme active site to generate cofactors which are essential for the catalytic enzymatic reaction. Significant questions remaining in copper-ion-mediated O2-activation in copper proteins are addressed.
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Affiliation(s)
- David A Quist
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Daniel E Diaz
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Jeffrey J Liu
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Kenneth D Karlin
- Department of Chemistry, Johns Hopkins University, Baltimore, MD, 21218, USA.
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Blemur L, Le TC, Marcocci L, Pietrangeli P, Mateescu MA. Carboxymethyl starch/alginate microspheres containing diamine oxidase for intestinal targeting. Biotechnol Appl Biochem 2016; 63:344-53. [PMID: 25779356 PMCID: PMC5034832 DOI: 10.1002/bab.1369] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 03/12/2015] [Indexed: 12/13/2022]
Abstract
The association of carboxymethyl starch (CMS) and alginate is proposed as a novel matrix for the entrapment of bioactive agents in microspheres affording their protection against gastrointestinal degradation. In this study, the enzyme diamine oxidase (DAO) from white pea (Lathyrus sativus) was immobilized by inclusion in microspheres formed by ionotropic gelation of CMS/alginate by complexation with Ca(2+) . The association of CMS to alginate generated a more compact structure presenting a lesser porosity, thus decreasing the access of gastric fluid inside the microspheres and preventing the loss of entrapped enzyme. Moreover, the immobilized enzyme remained active and was able to oxidize the polyamine substrates even in the presence of degrading proteases of pancreatin. The inclusion yield in terms of entrapped protein was of about 82%-95%. The DAO entrapped in calcium CMS/alginate beads retained up to 70% of its initial activity in simulated gastric fluid (pH 2.0). In simulated intestinal fluid (pH 7.2) with pancreatin, an overall retention of 65% of activity for the immobilized DAO was observed over 24 H, whereas in similar conditions the free enzyme was totally inactivated. Our project proposes the vegetal DAO as an antihistaminic agent orally administered to treat food histaminosis and colon inflammation.
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Affiliation(s)
- Lindsay Blemur
- Department of Chemistry & Centre BioMedUniversité du Québec à MontrealMontrealQCCanada
| | - Tien Canh Le
- Department of Chemistry & Centre BioMedUniversité du Québec à MontrealMontrealQCCanada
| | - Lucia Marcocci
- Department of Biochemical Sciences“A. Rossi‐Fanelli,” University of Rome “La Sapienza,”RomeItaly
| | - Paola Pietrangeli
- Department of Biochemical Sciences“A. Rossi‐Fanelli,” University of Rome “La Sapienza,”RomeItaly
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Sehanobish E, Campillo-Brocal JC, Williamson HR, Sanchez-Amat A, Davidson VL. Interaction of GoxA with Its Modifying Enzyme and Its Subunit Assembly Are Dependent on the Extent of Cysteine Tryptophylquinone Biosynthesis. Biochemistry 2016; 55:2305-8. [PMID: 27064961 DOI: 10.1021/acs.biochem.6b00274] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
GoxA is a glycine oxidase bearing a protein-derived cysteine tryptophylquinone (CTQ) cofactor that is formed by posttranslational modifications catalyzed by a flavoprotein, GoxB. Two forms of GoxA were isolated: an active form with mature CTQ and an inactive precursor protein that lacked CTQ. The active GoxA was present as a homodimer with no detectable affinity for GoxB, whereas the precursor was isolated as a monomer in a tight complex with one GoxB. Thus, the interaction of GoxA with GoxB and subunit assembly of mature GoxA are each dependent on the extent of CTQ biosynthesis.
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Affiliation(s)
- Esha Sehanobish
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida 32827, United States
| | | | - Heather R Williamson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida 32827, United States
| | - Antonio Sanchez-Amat
- Department of Genetics and Microbiology, University of Murcia , Murcia 30100, Spain
| | - Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida , Orlando, Florida 32827, United States
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Primary Amine Oxidase of Escherichia coli Is a Metabolic Enzyme that Can Use a Human Leukocyte Molecule as a Substrate. PLoS One 2015; 10:e0142367. [PMID: 26556595 PMCID: PMC4640556 DOI: 10.1371/journal.pone.0142367] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/21/2015] [Indexed: 12/17/2022] Open
Abstract
Escherichia coli amine oxidase (ECAO), encoded by the tynA gene, catalyzes the oxidative deamination of aromatic amines into aldehydes through a well-established mechanism, but its exact biological role is unknown. We investigated the role of ECAO by screening environmental and human isolates for tynA and characterizing a tynA-deletion strain using microarray analysis and biochemical studies. The presence of tynA did not correlate with pathogenicity. In tynA+ Escherichia coli strains, ECAO enabled bacterial growth in phenylethylamine, and the resultant H2O2 was released into the growth medium. Some aminoglycoside antibiotics inhibited the enzymatic activity of ECAO, which could affect the growth of tynA+ bacteria. Our results suggest that tynA is a reserve gene used under stringent environmental conditions in which ECAO may, due to its production of H2O2, provide a growth advantage over other bacteria that are unable to manage high levels of this oxidant. In addition, ECAO, which resembles the human homolog hAOC3, is able to process an unknown substrate on human leukocytes.
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Moon HJ, Finney J, Ronnebaum T, Mure M. Human lysyl oxidase-like 2. Bioorg Chem 2014; 57:231-241. [PMID: 25146937 DOI: 10.1016/j.bioorg.2014.07.003] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/10/2014] [Accepted: 07/14/2014] [Indexed: 12/31/2022]
Abstract
Lysyl oxidase like-2 (LOXL2) belongs to the lysyl oxidase (LOX) family, which comprises Cu(2+)- and lysine tyrosylquinone (LTQ)-dependent amine oxidases. LOXL2 is proposed to function similarly to LOX in the extracellular matrix (ECM) by promoting crosslinking of collagen and elastin. LOXL2 has also been proposed to regulate extracellular and intracellular cell signaling pathways. Dysregulation of LOXL2 has been linked to many diseases, including cancer, pro-oncogenic angiogenesis, fibrosis and heart diseases. In this review, we will give an overview of the current understandings and hypotheses regarding the molecular functions of LOXL2.
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Affiliation(s)
- Hee-Jung Moon
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Joel Finney
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Trey Ronnebaum
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Minae Mure
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA.
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Klinman JP, Bonnot F. Intrigues and intricacies of the biosynthetic pathways for the enzymatic quinocofactors: PQQ, TTQ, CTQ, TPQ, and LTQ. Chem Rev 2014; 114:4343-65. [PMID: 24350630 PMCID: PMC3999297 DOI: 10.1021/cr400475g] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Judith P. Klinman
- Department of Chemistry University of California, Berkeley, California 94720, U.S.A. Supported by the National Institutes of Health (GM025765) to J.P.K
- Department of Molecular and Cell Biology University of California, Berkeley, California 94720, U.S.A. Supported by the National Institutes of Health (GM025765) to J.P.K
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, U.S.A. Supported by the National Institutes of Health (GM025765) to J.P.K
| | - Florence Bonnot
- Department of Chemistry University of California, Berkeley, California 94720, U.S.A. Supported by the National Institutes of Health (GM025765) to J.P.K
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, U.S.A. Supported by the National Institutes of Health (GM025765) to J.P.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: 1126] [Impact Index Per Article: 112.6] [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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Finney J, Moon HJ, Ronnebaum T, Lantz M, Mure M. Human copper-dependent amine oxidases. Arch Biochem Biophys 2014; 546:19-32. [PMID: 24407025 DOI: 10.1016/j.abb.2013.12.022] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Revised: 12/24/2013] [Accepted: 12/26/2013] [Indexed: 12/11/2022]
Abstract
Copper amine oxidases (CAOs) are a class of enzymes that contain Cu(2+) and a tyrosine-derived quinone cofactor, catalyze the conversion of a primary amine functional group to an aldehyde, and generate hydrogen peroxide and ammonia as byproducts. These enzymes can be classified into two non-homologous families: 2,4,5-trihydroxyphenylalanine quinone (TPQ)-dependent CAOs and the lysine tyrosylquinone (LTQ)-dependent lysyl oxidase (LOX) family of proteins. In this review, we will focus on recent developments in the field of research concerning human CAOs and the LOX family of proteins. The aberrant expression of these enzymes is linked to inflammation, fibrosis, tumor metastasis/invasion and other diseases. Consequently, there is a critical need to understand the functions of these proteins at the molecular level, so that strategies targeting these enzymes can be developed to combat human diseases.
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Affiliation(s)
- Joel Finney
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Hee-Jung Moon
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Trey Ronnebaum
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Mason Lantz
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA
| | - Minae Mure
- Department of Chemistry, The University of Kansas, Lawrence, KS 66045, USA.
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Davidson VL, Wilmot CM. Posttranslational biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. Annu Rev Biochem 2013; 82:531-50. [PMID: 23746262 DOI: 10.1146/annurev-biochem-051110-133601] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Methylamine dehydrogenase (MADH) catalyzes the oxidative deamination of methylamine to formaldehyde and ammonia. Tryptophan tryptophylquinone (TTQ) is the protein-derived cofactor of MADH required for this catalytic activity. TTQ is biosynthesized through the posttranslational modification of two tryptophan residues within MADH, during which the indole rings of two tryptophan side chains are cross-linked and two oxygen atoms are inserted into one of the indole rings. MauG is a c-type diheme enzyme that catalyzes the final three reactions in TTQ formation. In total, this is a six-electron oxidation process requiring three cycles of MauG-dependent two-electron oxidation events using either H2O2 or O2. The MauG redox form responsible for the catalytic activity is an unprecedented bis-Fe(IV) species. The amino acids of MADH that are modified are ≈ 40 Å from the site where MauG binds oxygen, and the reaction proceeds by a hole hopping electron transfer mechanism. This review addresses these highly unusual aspects of the long-range catalytic reaction mediated by MauG.
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Affiliation(s)
- Victor L Davidson
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32827, USA.
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Abstract
Methylamine dehydrogenase (MADH) requires the cofactor tryptophan tryptophylquinone (TTQ) for activity. TTQ is a posttranslational modification that results from an 8-electron oxidation of two specific tryptophans in the MADH β-subunit. The final 6-electron oxidation is catalyzed by an unusual c-type di-heme enzyme, MauG. The di-ferric enzyme can react with H(2)O(2), but atypically for c-type hemes the di-ferrous enzyme can react with O(2) as well. In both cases, an unprecedented bis-Fe(IV) redox state is formed, composed of a ferryl heme (Fe(IV)=O) with the second heme as Fe(IV) stabilized by His-Tyr axial ligation. Bis-Fe(IV) MauG acts as a potent 2-electron oxidant. Catalysis is long-range and requires a hole hopping electron transfer mechanism. This review highlights the current knowledge and focus of research into this fascinating system.
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Affiliation(s)
- Carrie M Wilmot
- Department of Biochemistry, Molecular Biology and Biophysics, Minneapolis, Minnesota 55455, USA.
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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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Murakawa T, Hayashi H, Taki M, Yamamoto Y, Kawano Y, Tanizawa K, Okajima T. Structural insights into the substrate specificity of bacterial copper amine oxidase obtained by using irreversible inhibitors. J Biochem 2011; 151:167-78. [PMID: 21984603 DOI: 10.1093/jb/mvr125] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Copper amine oxidases (CAOs) catalyse the oxidation of various aliphatic amines to the corresponding aldehydes, ammonia and hydrogen peroxide. Although CAOs from various organisms share a highly conserved active-site structure including a protein-derived cofactor, topa quinone (TPQ), their substrate specificities differ considerably. To obtain structural insights into the substrate specificity of a CAO from Arthrobacter globiformis (AGAO), we have determined the X-ray crystal structures of AGAO complexed with irreversible inhibitors that form covalent adducts with TPQ. Three hydrazine derivatives, benzylhydrazine (BHZ), 4-hydroxybenzylhydrazine (4-OH-BHZ) and phenylhydrazine (PHZ) formed predominantly a hydrazone adduct, which is structurally analogous to the substrate Schiff base of TPQ formed during the catalytic reaction. With BHZ and 4-OH-BHZ, but not with PHZ, the inhibitor aromatic ring is bound to a hydrophobic cavity near the active site in a well-defined conformation. Furthermore, the hydrogen atom on the hydrazone nitrogen is located closer to the catalytic base in the BHZ and 4-OH-BHZ adducts than in the PHZ adduct. These results correlate well with the reactivity of 2-phenylethylamine and tyramine as preferred substrates for AGAO and also explain why benzylamine is a poor substrate with markedly decreased rate constants for the steps of proton abstraction and the following hydrolysis.
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Affiliation(s)
- Takeshi Murakawa
- Department of Biochemistry, Osaka Medical College, Osaka 569-8686, Japan
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Davidson VL. Generation of protein-derived redox cofactors by posttranslational modification. MOLECULAR BIOSYSTEMS 2010; 7:29-37. [PMID: 20936199 DOI: 10.1039/c005311b] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Redox enzymes which catalyze the oxidation and reduction of substrates are ubiquitous in nature. These enzymes typically possess exogenous cofactors to allow them to perform catalytic functions which cannot be accomplished using only amino acid residues. It is now evident that nature also employs an alternative strategy of generating catalytic and redox-active sites in proteins by posttranslational modification of amino acid residues. This review describes the structures and functions of several of these protein-derived cofactors and the diverse mechanisms of posttranslational modification through which they are generated.
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Affiliation(s)
- Victor L Davidson
- Department of Biochemistry, University of Mississippi Medical Center, 2500 N. State St, Jackson, Mississippi 39216-4505, USA.
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19
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Chen ZW, Datta S, Dubois JL, Klinman JP, Mathews FS. Mutation at a strictly conserved, active site tyrosine in the copper amine oxidase leads to uncontrolled oxygenase activity. Biochemistry 2010; 49:7393-402. [PMID: 20684524 DOI: 10.1021/bi100643y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The copper amine oxidases carry out two copper-dependent processes: production of their own redox-active cofactor (2,4,5-trihydroxyphenylalanine quinone, TPQ) and the subsequent oxidative deamination of substrate amines. Because the same active site pocket must facilitate both reactions, individual active site residues may serve multiple roles. We have examined the roles of a strictly conserved active site tyrosine Y305 in the copper amine oxidase from Hansenula polymorpha kinetically, spetroscopically (Dubois and Klinman (2006) Biochemistry 45, 3178), and, in the present work, structurally. While the Y305A enzyme is almost identical to the wild type, a novel, highly oxygenated species replaces TPQ in the Y305F active sites. This new structure not only provides the first direct detection of peroxy intermediates in cofactor biogenesis but also indicates the critical control of oxidation chemistry that can be conferred by a single active site residue.
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Affiliation(s)
- Zhi-Wei Chen
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, 660 South Euclid Avenue, Box 8231, St. Louis, Missouri 63110, USA
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20
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Ghosh S, Cirera J, Vance MA, Ono T, Fujisawa K, Solomon EI. Spectroscopic and electronic structure studies of phenolate Cu(II) complexes: phenolate ring orientation and activation related to cofactor biogenesis. J Am Chem Soc 2009; 130:16262-73. [PMID: 18998639 DOI: 10.1021/ja8044986] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A combination of spectroscopies and DFT calculations have been used to define the electronic structures of two crystallographically defined Cu(II)-phenolate complexes. These complexes differ in the orientation of the phenolate ring which results in different bonding interactions of the phenolate donor orbitals with the Cu(II), which are reflected in the very different spectroscopic properties of the two complexes. These differences in electronic structures lead to significant differences in DFT calculated reactivities with oxygen. These calculations suggest that oxygen activation via a Cu(I) phenoxyl ligand-to-metal charge transfer complex is highly endergonic (>50 kcal/mol), hence an unlikely pathway. Rather, the two-electron oxidation of the phenolate forming a bridging Cu(II) peroxoquinone complex is more favorable (11.3 kcal/mol). The role of the oxidized metal in mediating this two-electron oxidation of the coordinated phenolate and its relevance to the biogenesis of the covalently bound topa quinone in amine oxidase are discussed.
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Affiliation(s)
- Somdatta Ghosh
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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21
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Copper distributed by Atx1 is available to copper amine oxidase 1 in Schizosaccharomyces pombe. EUKARYOTIC CELL 2008; 7:1781-94. [PMID: 18723604 DOI: 10.1128/ec.00230-08] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Copper amine oxidases (CAOs) have been proposed to be involved in the metabolism of xenobiotic and biogenic amines. The requirement for copper is absolute for their activity. In the fission yeast Schizosaccharomyces pombe, cao1(+) and cao2(+) genes are predicted to encode members of the CAO family. While both genes are expressed in wild-type cells, we determined that the expression of only cao1(+) but not cao2(+) results in the production of an active enzyme. Site-directed mutagenesis identified three histidine residues within the C-terminal region of Cao1 that are necessary for amine oxidase activity. By use of a cao1(+)-GFP allele that retained wild-type function, Cao1-GFP was localized in the cytosol (GFP is green fluorescent protein). Under copper-limiting conditions, disruption of ctr4(+), ctr5(+), and cuf1(+) produced a defect in amine oxidase activity, indicating that a functionally active Cao1 requires Ctr4/5-mediated copper transport and the transcription factor Cuf1. Likewise, atx1 null cells exhibited substantially decreased levels of amine oxidase activity. In contrast, deletion of ccc2, cox17, and pccs had no significant effect on Cao1 activity. Residual amine oxidase activity in cells lacking atx1(+) can be restored to normal levels by returning an atx1(+) allele, underscoring the critical importance of the presence of Atx1 in cells. Using two-hybrid analysis, we demonstrated that Cao1 physically interacts with Atx1 and that this association is comparable to that of Atx1 with the N-terminal region of Ccc2. Collectively, these results describe the first example of the ability of Atx1 to act as a copper carrier for a molecule other than Ccc2 and its critical role in delivering copper to Cao1.
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22
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Cuzzocrea S, Masini E. Plant histaminase as an investigational drug in splanchnic artery occlusion and reperfusion. Expert Opin Investig Drugs 2008; 17:1151-60. [PMID: 18616412 DOI: 10.1517/13543784.17.8.1151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Amine oxidases are ubiquitous enzymes involved in the metabolism of biogenic amines. Copper amine oxidases catalyze the oxidative deamination of primary amine groups of several biogenic amines, such as putrescine, cadaverine and histamine. OBJECTIVE In the present review the effects of a plant amine oxidase (histaminase, EC1.4.3.6), purified from pea seedlings, in the prevention of splanchnic postischemic reperfusion damage are reported. CONCLUSION Various studies have clearly indicated that the use of histaminase will offer a good perspective for a novel therapeutic approach in the medical treatment of intestinal ischemia.
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Affiliation(s)
- Salvatore Cuzzocrea
- University of Messina, School of Medicine, Department of Clinical, Experimental Medicine and Pharmacology, Torre Biologica-Policlinico Universitario, Via Consolare Valeria-Gazzi, 98100 Messina, Italy.
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23
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Pietrangeli P, Federico R, Mondovì B, Morpurgo L. Substrate specificity of copper-containing plant amine oxidases. J Inorg Biochem 2007; 101:997-1004. [PMID: 17521737 DOI: 10.1016/j.jinorgbio.2007.03.014] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2006] [Revised: 03/22/2007] [Accepted: 03/28/2007] [Indexed: 10/23/2022]
Abstract
The steady-state kinetic parameters of the amine oxidases purified from Lathyrus cicera (LCAO) and Pisum sativum (PSAO) seedling were measured on a series of common substrates, previously tested on bovine serum amine oxidase (BSAO). LCAO, as PSAO, was substantially more reactive than BSAO with aliphatic diamines and histamine. The k(cat) and k(cat)/Km for putrescine were four and six order of magnitude higher, respectively. Differences were smaller with some aromatic monoamines. The plot of k(cat) versus hydrogen ions concentration produced bell-shaped curves, the maximum of which was substrate dependent, shifting from neutral pH with putrescine to alkaline pH with phenylethylamine and benzylamine. The latter substrates made the site more hydrophobic and increased the pK(a) of both enzyme-substrate and enzyme-product adducts. The plot of k(cat)/Km versus hydrogen ion concentration produced approximately parallel bell-shaped curves. Similar pK(a) couples were obtained from the latter curves, in agreement with the assignment as free enzyme and free substrate pK(a). The limited pH dependence of kinetic parameters suggests a predominance of hydrophobic interactions.
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Affiliation(s)
- P Pietrangeli
- Department of Biochemical Sciences, A. Rossi Fanelli, University of Rome La Sapienza, P.le A. Moro 5, 00185 Rome, Italy.
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24
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Laliberté J, Labbé S. Mechanisms of copper loading on the Schizosaccharomyces pombe copper amine oxidase 1 expressed in Saccharomyces cerevisiae. MICROBIOLOGY (READING, ENGLAND) 2006; 152:2819-2830. [PMID: 16946276 DOI: 10.1099/mic.0.28998-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Copper amine oxidases (CAOs) are found in almost every living kingdom. Although Saccharomyces cerevisiae is one of the few yeast species that lacks an endogenous CAO, heterologous gene expression of CAOs from other organisms produces a functional enzyme. To begin to characterize their function and mechanisms of copper acquisition, two putative cao(+) genes from Schizosaccharomyces pombe were expressed in S. cerevisiae. Expression of spao1(+) resulted in the production of an active enzyme capable of catalysing the oxidative deamination of primary amines. On the other hand, expression of spao2(+) failed to produce an active CAO. Using a functional spao1(+)-GFP fusion allele, the SPAO1 protein was localized in the cytosol. Under copper-limiting conditions, yeast cells harbouring deletions of the MAC1, CTR1 and CTR3 genes were defective in amine oxidase activity. Likewise, atx1Delta null cells exhibited no CAO activity, while ccc2Delta mutant cells exhibited decreased levels of amine oxidase activity, and mutations in cox17Delta and ccs1Delta did not cause any defects in this activity. Copper-deprived S. cerevisiae cells expressing spao1(+) required a functional atx1(+) gene for growth on minimal medium containing ethylamine as the sole nitrogen source. Under these conditions, the inability of the atx1Delta cells to utilize ethylamine correlated with the lack of SPAO1 activity, in spite of the efficient expression of the protein. Cells carrying a disrupted ccc2Delta allele exhibited only weak growth on ethylamine medium containing a copper chelator. The results of these studies reveal that expression of the heterologous spao1(+) gene in S. cerevisiae is required for its growth in medium containing ethylamine as the sole nitrogen source, and that expression of an active Schiz. pombe SPAO1 protein in S. cerevisiae depends on the acquisition of copper through the high-affinity copper transporters Ctr1 and Ctr3, and the copper chaperone Atx1.
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Affiliation(s)
- Julie Laliberté
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
| | - Simon Labbé
- Département de Biochimie, Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada
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25
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Longu S, Mura A, Padiglia A, Medda R, Floris G. Mechanism-based inactivators of plant copper/quinone containing amine oxidases. PHYTOCHEMISTRY 2005; 66:1751-8. [PMID: 16054177 DOI: 10.1016/j.phytochem.2005.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2005] [Revised: 06/15/2005] [Accepted: 06/15/2005] [Indexed: 05/03/2023]
Abstract
Copper/quinone amine oxidases contain Cu(II) and the quinone of 2,4,5-trihydroxyphenylalanine (topaquinone; TPQ) as cofactors. TPQ is derived by post-translational modification of a conserved tyrosine residue in the protein chain. Major advances have been made during the last decade toward understanding the structure/function relationships of the active site in Cu/TPQ amine oxidases using specific inhibitors. Mechanism-based inactivators are substrate analogues that bind to the active site of an enzyme being accepted and processed by the normal catalytic mechanism of the enzyme. During the reaction a covalent modification of the enzyme occurs leading to irreversible inactivation. In this review mechanism-based inactivators of plant Cu/TPQ amine oxidases from the pulses lentil (Lens esculenta), pea (Pisum sativum), grass pea (Lathyrus sativus) and sainfoin (Onobrychis viciifolia,) are described. Substrates forming, in aerobiotic and in anaerobiotic conditions, killer products that covalently bound to the quinone cofactor or to a specific amino acid residue of the target enzyme are all reviewed.
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Affiliation(s)
- Silvia Longu
- Department of Applied Sciences in Biosystems, University of Cagliari, Cittadella Universitaria, I-09042 Cagliari, Italy
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26
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Dubois JL, Klinman JP. Mechanism of post-translational quinone formation in copper amine oxidases and its relationship to the catalytic turnover. Arch Biochem Biophys 2005; 433:255-65. [PMID: 15581581 DOI: 10.1016/j.abb.2004.08.036] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2004] [Revised: 08/31/2004] [Indexed: 11/22/2022]
Abstract
Copper amine oxidases (CAOs) post-translationally construct a redox-active quinone from an amino acid side chain in their polypeptide chain. As such, these enzymes illustrate how nature is able to expand upon naturally-occurring side chains to create new, catalytically powerful functionalities. The active sites of the CAOs are highly unusual in their ability to catalyze two very different reactions: single-turnover, oxygen-dependent quinone formation, followed by catalytic oxidation (formally dehydrogenation) of amines. This review summarizes our current understanding of the pathway whereby the 2,4,5-trihydroxyphenylalanyl quinone (TPQ) cofactor is generated from the phenolic side chain of tyrosine. This reaction occurs spontaneously intermediates in the presence of O(2) and active site bound Cu(II), without the assistance of other proteins or cofactors. Ongoing work has focused on uncovering the details of the TPQ formation mechanism. A larger goal is to understand how a single active site is capable of supporting both quinone formation and subsequent catalytic turnover.
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Affiliation(s)
- Jennifer L Dubois
- Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA
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27
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Davidson VL. Structure and mechanism of tryptophylquinone enzymes. Bioorg Chem 2004; 33:159-70. [PMID: 15888309 DOI: 10.1016/j.bioorg.2004.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 10/05/2004] [Accepted: 10/08/2004] [Indexed: 11/23/2022]
Abstract
Tryptophylquinone cofactors are formed by posttranslational modifications that result in the incorporation of two oxygens into a tryptophan side chain, and the covalent cross-linking of that side chain to another amino acid residue. Tryptophylquinone enzymes catalyze the oxidative deamination of primary amines, and utilize other redox proteins as electron acceptors. Mechanistic and structural studies of these enzymes are providing insight into how these enzymes utilize these highly reactive protein-derived quinones in a controlled manner to facilitate biologically important catalytic and electron transfer reactions.
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Affiliation(s)
- Victor L Davidson
- Department of Biochemistry, The University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216-4505, USA.
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28
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Affiliation(s)
- Jennifer L DuBois
- Department of Chemistry,University of California, Berkeley 94720, USA
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29
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Pietrangeli P, Nocera S, Federico R, Mondovì B, Morpurgo L. Inactivation of copper-containing amine oxidases by turnover products. ACTA ACUST UNITED AC 2003; 271:146-52. [PMID: 14686927 DOI: 10.1046/j.1432-1033.2003.03913.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
For bovine serum amine oxidase, two different mechanisms of substrate-induced inactivation have been proposed. One consists of a slow oxidation by H2O2 of a conserved residue in the reduced enzyme after the fast turnover phase [Pietrangeli, P., Nocera, S., Fattibene, P., Wang, X.T., Mondovì, B. & Morpurgo, L. (2000) Biochem. Biophys. Res. Commun.267, 174-178] and the other of the oxidation by H2O2 of the dihydrobenzoxazole in equilibrium with the product Schiff base, during the catalytic cycle [Lee, Y., Shepard, E., Smith, J., Dooley, D.M. & Sayre, L.M. (2001) Biochemistry40, 822-829]. To discriminate between the two mechanisms, the inactivation was studied using Lathyrus cicera (red vetchling) amine oxidase. This, in contrast to bovine serum amine oxidase, formed the Cu+-semiquinolamine radical with a characteristic UV-vis spectrum when oxygen was exhausted by an excess of any tested amine in a closed cuvette. The inactivation, lasting about 90 min, was simultaneous with the radical decay and with the formation of a broad band (shoulder) at 350 nm. No inactivation occurred when a thousand-fold excess of amine was rapidly oxidized in an L. cicera amine oxidase solution stirred in open air. Thus, the inactivation is a slow reaction of the reduced enzyme with H2O2, following the turnover phase. Catalase protected L. cicera amine oxidase from inactivation. This effect was substrate-dependent, varying from full protection (benzylamine) to no protection (putrescine). In the absence of H2O2, a specific inactivating reaction, without formation of the 350 nm band, was induced by some aldehydes, notably putrescine. Some mechanisms of inactivation are proposed.
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Affiliation(s)
- Paola Pietrangeli
- Department of Biochemical Sciences A. Rossi Fanelli and C.N.R. Institute of Molecular Biology and Pathology, University of Rome La Sapienza, Rome, Italy.
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30
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Prabhakar R, Siegbahn PEM. A comparison of the mechanism for the reductive half-reaction between pea seedling and other copper amine oxidases (CAOs). J Comput Chem 2003; 24:1599-609. [PMID: 12926004 DOI: 10.1002/jcc.10282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
In a previous DFT study a mechanism for the reductive half-reaction of pea seedling amine oxidase (PSAO) was suggested. In many of the suggested steps a lysine at the active site plays an important role. However, this lysine is not found in other amine oxidases. The primary aim of the present DFT study is therefore to investigate alternative mechanisms for those amine oxidases (CAO) where the lysine residue is not present. One of the most important roles suggested for the lysine in PSAO was to protonate the O2-site of TPQ before the critical Cbond;H bond cleavage of the substrate. In the absence of lysine the O2-site of TPQ is now suggested to be protonated by a water ligand on the copper metal complex, in line with experimental suggestions. In other steps the role of lysine is taken over by an asparagine. All results are compared with experimental observations and good agreement is generally found.
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Affiliation(s)
- Rajeev Prabhakar
- Stockholm Centre for Physics, Astronomy and Biotechnology, Stockholm University, S-106 91 Stockholm, Sweden.
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31
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Pietrangeli P, Nocera S, Mondovi B, Morpurgo L. Is the catalytic mechanism of bacteria, plant, and mammal copper-TPQ amine oxidases identical? BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1647:152-6. [PMID: 12686125 DOI: 10.1016/s1570-9639(03)00083-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This short review is mostly concerned with the work carried out in Rome on the copper amine oxidase from bovine serum (BSAO). The first target was the copper oxidation state and its relationship with the organic cofactor. It was found that copper is not reduced on reaction with amines under anaerobic conditions or along the catalytic cycle and that it is not within bonding distance of the quinone cofactor. The copper stability in the oxidised state was supported by BSAO ability to oxidise benzylhydrazine, a slow substrate, in the presence of N,N-diethyldithiocarbamate (DDC) and by the substantial catalytic activity of Co(2+)-substituted BSAO. Parallel work established that only one subunit of the dimeric enzyme readily binds reagents of the carbonyl group. Flexible hydrazides with a long aromatic tail were found to be highly specific inhibitors, suggesting the presence of an extended hydrophobic region at the catalytic site. A study by stopped-flow transient spectroscopy and steady state kinetics led to the formulation of a simplified, yet complete and consistent, catalytic mechanism for BSAO that was compared with that available for lentil seedling amine oxidase (LSAO). As in other copper amine oxidases, BSAO is inactivated by H(2)O(2) produced in the catalytic reaction, while the cofactor is stabilised in its reduced state. A conserved tyrosine hydrogen-bonded to the cofactor might be oxidised.
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Affiliation(s)
- P Pietrangeli
- Department of Biochemical Sciences A. Rossi Fanelli and C.N.R. Centre of Molecular Biology, La Sapienza, University, P.le A. Moro 5, 00185 Rome, Italy
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32
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Prabhakar R, Siegbahn PEM, Minaev BF. A theoretical study of the dioxygen activation by glucose oxidase and copper amine oxidase. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1647:173-8. [PMID: 12686129 DOI: 10.1016/s1570-9639(03)00090-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Glucose oxidase (GO) and copper amine oxidase (CAO) catalyze the reduction of molecular oxygen to hydrogen peroxide. If a closed-shell cofactor (like FADH(2) in GO and topaquinone (TPQ) in CAO) is electron donor in dioxygen reduction, the formation of a closed-shell species (H(2)O(2)) is a spin forbidden process. Both in GO and CAO, formation of a superoxide ion that leads to the creation of a radical pair is experimentally suggested to be the rate-limiting step in the dioxygen reduction process. The present density functional theory (DFT) studies suggest that in GO, the creation of the radical pair induces a spin transition by spin orbit coupling (SOC) in O(2)(-)(rad), whereas in CAO, it is induced by exchange interaction with the paramagnetic metal ion (Cu(II)). In the rate-limiting step, this spin-transition is suggested to transform the O(2)(-)(rad)-FADH(2)(+)(rad) radical pair in GO and the Cu(II)-TPQ (triplet) species in CAO, from a triplet (T) to a singlet (S) state. For CAO, a mechanism for the O[bond]O cleavage step in the biogenesis of TPQ is also suggested.
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Affiliation(s)
- Rajeev Prabhakar
- Department of Physics, Stockholm Centre for Physics, Astronomy and Biotechnology (SCFAB), Stockholm University, S-106 91 Stockholm, Sweden
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33
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Abstract
The free radical-coupled copper catalytic motif has emerged as the unifying feature of a new family of enzymes, the radical copper oxidases. Their highly evolved active sites include a novel amino acid modification, the Tyr-Cys dimer, that forms spontaneously through self-processing of the protein during its maturation. The active site is remarkable in the extent to which metal ligands participate in the catalytic process. Rather than simply coordinating the metal ion, the ligands perform essential redox and proton-transfer functions in the chemistry of the active site, directed by their interactions with the copper center in the protein. The wide phylogenetic distribution and range of functions represented within the family hint of a fundamental role for these enzymes in the biology of oxygen. The roles for these enzymes are further expanding through a variety of biotechnological applications.
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Affiliation(s)
- James W Whittaker
- Department of Biochemistry and Molecular Biology, OGI School of Science and Engineering, OHSU, Beaverton, Oregon 97006, USA
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34
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Shepard EM, Smith J, Elmore BO, Kuchar JA, Sayre LM, Dooley DM. Towards the development of selective amine oxidase inhibitors. Mechanism-based inhibition of six copper containing amine oxidases. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3645-58. [PMID: 12153561 DOI: 10.1046/j.1432-1033.2002.03035.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Four substrate analogs, 4-(2-naphthyloxy)-2-butyn-1-amine (1), 1,4-diamino-2-chloro-2-butene (2), 1,6-diamino-2,4-hexadiyne (3), and 2-chloro-5-phthalimidopentylamine (4) have been tested as inhibitors against mammalian, plant, bacterial, and fungal copper-containing amine oxidases: bovine plasma amine oxidase (BPAO), equine plasma amine oxidase (EPAO), pea seedling amine oxidase (PSAO), Arthrobacter globiformis amine oxidase (AGAO), Escherichia coli amine oxidase (ECAO), and Pichia pastoris lysyl oxidase (PPLO). Reactions of 1,4-diamino-2-butyne with selected amine oxidases were also examined. Each substrate analog contains a functional group that chemical precedent suggests could produce mechanism-based inactivation. Striking differences in selectivity and rates of inactivation were observed. For example, between two closely related plasma enzymes, BPAO is more sensitive than EPAO to 1 and 3, while the reverse is true for 2 and 4. In general, inactivation appears to arise in some cases from TPQ cofactor modification and in other cases from alkylation of protein residues in a manner that blocks access of substrate to the active site. Notably, 1 completely inhibits AGAO at stoichiometric concentrations and is not a substrate, but is an excellent substrate of PSAO and inhibition is observed only at very high concentrations. Structural models of 1 in Schiff base linkage to the TPQ cofactor in AGAO and PSAO (for which crystal structures are available) reveal substantial differences in the degree of interaction of bound 1 with side-chain residues, consistent with the widely divergent activities. Collectively, these results suggest that the development of highly selective amine oxidase inhibitors is feasible.
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Affiliation(s)
- Eric M Shepard
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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35
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Rogers MS, Dooley DM. Posttranslationally modified tyrosines from galactose oxidase and cytochrome c oxidase. ADVANCES IN PROTEIN CHEMISTRY 2002; 58:387-436. [PMID: 11665492 DOI: 10.1016/s0065-3233(01)58009-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- M S Rogers
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, USA
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36
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Dove JE, Klinman JP. Trihydroxyphenylalanine quinone (TPQ) from copper amine oxidases and lysyl tyrosylquinone (LTQ) from lysyl oxidase. ADVANCES IN PROTEIN CHEMISTRY 2002; 58:141-74. [PMID: 11665487 DOI: 10.1016/s0065-3233(01)58004-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- J E Dove
- Departments of Chemistry and Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
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37
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Copper/topa quinone-containing amine oxidases — Recent research developments. ACTA ACUST UNITED AC 2002. [DOI: 10.1016/s1572-5995(02)80028-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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38
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Affiliation(s)
- J P Klinman
- Department of Chemistry, University of California, Berkeley, CA 94720, USA.
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Xie L, van der Donk WA. Homemade cofactors: self-processing in galactose oxidase. Proc Natl Acad Sci U S A 2001; 98:12863-5. [PMID: 11698675 PMCID: PMC60785 DOI: 10.1073/pnas.231485998] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- L Xie
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Box 38-5, Urbana, IL 61801, USA
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Juda GA, Bollinger JA, Dooley DM. Construction, overexpression, and purification of Arthrobacter globiformis amine oxidase-Strep-tag II fusion protein. Protein Expr Purif 2001; 22:455-61. [PMID: 11483008 DOI: 10.1006/prep.2001.1468] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The copper-containing amine oxidase from Arthrobacter globiformis has been expressed and purified as a fusion protein with a C-terminal Strep-tag II peptide. This tag facilitates the rapid purification of the enzyme on a large scale using the StrepTactin POROS medium. For example, we have demonstrated that 50 mg of protein can be obtained in 2 days from 2 L of Escherichia coli. The purified fusion protein displays turnover and spectroscopic properties that are essentially identical to those of the wild-type enzyme. Given the location of the C-terminus in four amine oxidase crystal structures, this strategy should be quite general for the rapid purification of amine oxidases from multiple sources.
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Affiliation(s)
- G A Juda
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, USA
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Schwartz B, Klinman JP. Mechanisms of biosynthesis of protein-derived redox cofactors. VITAMINS AND HORMONES 2001; 61:219-39. [PMID: 11153267 DOI: 10.1016/s0083-6729(01)61007-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Prior to 1990, redox cofactors were widely believed to be small molecule, dissociable compounds. In the past 10 years, however, four novel redox cofactors have been discovered, each of which is derived from posttranslational modification of specific amino acids within their cognate enzymes. These include topa quinone, found in copper amine oxidases, lysine tyrosyl quinone, found in lysyl oxidase, tryptophan tryptophylquinone, found in methylamine dehydrogenase, and the cysteine-cross-linked tyrosine found in galactose oxidase. The processes by which these cofactors are formed, called biogenesis, is currently a major focus of mechanistic work in this field. In this review, the latest progress toward elucidating the various biogenesis mechanisms is discussed, along with possible linkages between the chemistries involved in catalysis and biogenesis.
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Affiliation(s)
- B Schwartz
- Departments of Chemistry and Molecular Biology, University of California, Berkeley, California 94704, USA
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Okeley NM, van der Donk WA. Novel cofactors via post-translational modifications of enzyme active sites. CHEMISTRY & BIOLOGY 2000; 7:R159-71. [PMID: 10903941 DOI: 10.1016/s1074-5521(00)00140-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent crystallographic and biochemical studies have revealed the existence of numerous novel post-translational modifications within enzyme active sites. These modifications create structural and functional diversity. Although the function and biosynthesis of some of these modifications are well understood, others need further investigation.
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Affiliation(s)
- N M Okeley
- Department of Chemistry, University of Illinois at Urbana-Champaign, 61801, USA
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Bisby RH, Johnson SA, Parker AW. Radicals from One-Electron Oxidation of 4-Aminoresorcinol: Models for the Active Site Radical Intermediate in Copper Amine Oxidases. J Phys Chem B 2000. [DOI: 10.1021/jp000296v] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Roger H. Bisby
- Department of Biological Sciences, University of Salford, Salford M5 4WT, U.K
| | - Steven A. Johnson
- Department of Biological Sciences, University of Salford, Salford M5 4WT, U.K
| | - Anthony W. Parker
- Lasers for Science Facility, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, OX11 OQX, U.K
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Davidson VL. Structure, function, and applications of tryptophan tryptophylquinone enzymes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2000; 467:587-95. [PMID: 10721104 DOI: 10.1007/978-1-4615-4709-9_73] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Tryptophan and tyrosine residues in proteins may be posttranslationally modified to form enzyme cofactors. Tryptophan tryptophylquinone (TTQ), the cofactor of methylamine dehydrogenase (MADH), is formed by covalent cross-linking of two tryptophan residues and incorporation of two oxygen atoms into one of the indole rings to form a quinone. MADH converts primary amines to their corresponding aldehydes plus ammonia. During the catalytic cycle, TTQ mediates electron transfer from substrate to a copper protein, amicyanin. These electrons are transferred to the respiratory chain via a c-type cytochrome. Structural, kinetic and site-directed mutagenesis studies have characterized protein-protein interactions, and mechanisms of catalysis and electron transfer by TTQ. Preliminary results obtained with MADH enzyme-electrodes demonstrate the potential for quinoprotein-based biosensors.
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Affiliation(s)
- V L Davidson
- Department of Biochemistry, University of Mississippi Medical Center, Jackson 39216, USA.
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Pietrangeli P, Nocera S, Fattibene P, Wang X, Mondovì B, Morpurgo L. Modulation of bovine serum amine oxidase activity by hydrogen peroxide. Biochem Biophys Res Commun 2000; 267:174-8. [PMID: 10623594 DOI: 10.1006/bbrc.1999.1925] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Bovine serum amine oxidase (BSAO), reduced by excess amine under limited turnover conditions, was over 80% inactivated by H(2)O(2) upon oxygen exhaustion. The UV-Vis spectrum and the reduced reactivity with carbonyl reagents showed that the cofactor topaquinone (TPQ) was stabilized in reduced form. The protein large M(r) (170 kDa) prevented the identification of modified residues by amino acid analyses. Minor changes of the Cu(2+) EPR signal and the formation of a radical at g = 2.001, with intensity a few percent of that of the Cu(2+) signal, unaffected by a temperature increase, suggest that Cu(2+)-bound histidines were not oxidized and the radical was not the Cu(+)-semiquinolamine in equilibrium with Cu(2+)-aminoquinol. It may derive from the modification of a conserved residue in proximity of the active site, possibly the tyrosine at hydrogen-bonding distance of TPQ C-4 ionized hydroxyl. The inactivation reaction appears to be a general feature of copper-containing amine oxidases. It may be part of an autoregulatory process in vivo, possibly relevant to cell adhesion and redox signaling.
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Affiliation(s)
- P Pietrangeli
- Centro di Biologia Molecolare del CNR, Università "La Sapienza,", P. le A. Moro 5, Rome, 00185, Italy
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Williams NK, Klinman JP. Whence topa? Models for the biogenesis of topa quinone in copper amine oxidases. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1381-1177(99)00071-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Padiglia A, Medda R, Pedersen JZ, Lorrai A, Pec P, Frébort I, Floris G. Inhibitors of plant copper amine oxidases. JOURNAL OF ENZYME INHIBITION 1998; 13:311-25. [PMID: 9793836 DOI: 10.3109/14756369809021478] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
In this review, inhibitors of plant copper amine oxidases from Lens esculenta seedlings, Pisum sativum seedlings, and Euphorbia characias latex are described. Reversible competitive inhibitors and non-competitive inhibitors, irreversible active-site directed inhibitors and mechanism-based inactivators are reviewed in regard to their mechanisms of action.
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Affiliation(s)
- A Padiglia
- Department of Biochemistry and Human Physiology, University of Cagliari, Italy
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Padiglia A, Medda R, Lorrai A, Murgia B, Pedersen JZ, Finazzi Agró A, Floris G. Characterization of Euphorbia characias latex amine oxidase. PLANT PHYSIOLOGY 1998; 117:1363-1371. [PMID: 9701592 PMCID: PMC34900 DOI: 10.1104/pp.117.4.1363] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/1998] [Accepted: 05/12/1998] [Indexed: 05/22/2023]
Abstract
A copper-containing amine oxidase from the latex of Euphorbia characias was purified to homogeneity and the copper-free enzyme obtained by a ligand-exchange procedure. The interactions of highly purified apo- and holoenzyme with several substrates, carbonyl reagents, and copper ligands were investigated by optical spectroscopy under both aerobic and anaerobic conditions. The extinction coefficients at 278 and 490 nm were determined as 3.78 x 10(5) M-1 cm-1 and 6000 M-1 cm-1, respectively. Active-site titration of highly purified enzyme with substrates and carbonyl reagents showed the presence of one cofactor at each enzyme subunit. In anaerobiosis the native enzyme oxidized one equivalent substrate and released one equivalent aldehyde per enzyme subunit. The apoenzyme gave exactly the same 1:1:1 stoichiometry in anaerobiosis and in aerobiosis. These findings demonstrate unequivocally that copper-free amine oxidase can oxidize substrates with a single half-catalytic cycle. The DNA-derived protein sequence shows a characteristic hexapeptide present in most 6-hydroxydopa quinone-containing amine oxidases. This hexapeptide contains the tyrosinyl residue that can be modified into the cofactor 6-hydroxydopa quinone.
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Affiliation(s)
- A Padiglia
- Department of Biochemistry and Human Physiology, University of Cagliari, Cagliari, Italy
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50
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Li R, Klinman JP, Mathews FS. Copper amine oxidase from Hansenula polymorpha: the crystal structure determined at 2.4 A resolution reveals the active conformation. Structure 1998; 6:293-307. [PMID: 9551552 DOI: 10.1016/s0969-2126(98)00033-1] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Copper-containing amine oxidases (CAOs) are widespread in nature. These enzymes oxidize primary amine substrates to the aldehyde product, reducing molecular oxygen to hydrogen peroxide in the process. CAOs contain one type 2 copper atom and topaquinone (TPQ), a modified tyrosine sidechain utilized as a redox cofactor. The methylamine oxidase from the yeast Hansenula polymorpha (HPAO) is an isoform of CAO with a preference for small aliphatic amine or phenethylamine substrates. The enzyme is dimeric with a subunit molecular weight of 78 kDa. Structural studies are directed at understanding the basis for cofactor biogenesis and catalytic efficiency. RESULTS The X-ray crystal structure of HPAO has been solved at 2.4 A resolution by a combination of molecular replacement and single isomorphous replacement followed by refinement using sixfold symmetry averaging. The electron density at the catalytic site shows that the TPQ conformation corresponds to that of the active form of the enzyme. Two channels, one on either side of TPQ, are observed in the structure that provide access between the active site and the bulk solvent. CONCLUSIONS The structure shows TPQ in a position poised for catalysis. This is the first active CAO structure to reveal this conformation and may help further our understanding of the catalytic mechanism. On the substrate side of TPQ a water-containing channel leading to the protein surface can serve as an entrance or exit for substrate and product. On the opposite side of TPQ there is direct access from the bulk solvent of the dimer interface by which molecular oxygen may enter and hydrogen peroxide depart. In addition, a network of conserved water molecules has been identified which may function in the catalytic mechanism.
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Affiliation(s)
- R Li
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO 63110, USA
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