1
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A rigorous theory of valence. Struct Chem 2023. [DOI: 10.1007/s11224-023-02128-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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2
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Merkler DJ, Hawley AJ, Eipper BA, Mains RE. Peptidylglycine α-amidating monooxygenase as a therapeutic target or biomarker for human diseases. Br J Pharmacol 2022; 179:3306-3324. [PMID: 35124797 PMCID: PMC9177522 DOI: 10.1111/bph.15815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 01/20/2024] Open
Abstract
Peptides play a key role in controlling many physiological and neurobiological pathways. Many bioactive peptides require a C-terminal α-amide for full activity. The bifunctional enzyme catalysing α-amidation, peptidylglycine α-amidating monooxygenase (PAM), is the sole enzyme responsible for amidated peptide biosynthesis, from Chlamydomonas reinhardtii to Homo sapiens. Many neuronal and endocrine functions are dependent upon amidated peptides; additional amidated peptides are growth promoters in tumours. The amidation reaction occurs in two steps, glycine α-hydroxylation followed by dealkylation to generate the α-amide product. Currently, most potentially useful inhibitors target the first reaction, which is rate-limiting. PAM is a membrane-bound enzyme that visits the cell surface during peptide secretion. PAM is then used again in the biosynthetic pathway, meaning that cell-impermeable inhibitors or inactivators could have therapeutic value for the treatment of cancer or psychiatric abnormalities. To date, inhibitor design has not fully exploited the structures and mechanistic details of PAM.
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Affiliation(s)
- David J Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Aidan J Hawley
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Betty A Eipper
- Department of Molecular Biology & Biophysics, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
| | - Richard E Mains
- Department of Neuroscience, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT, 06030 USA
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Theoretical perspective on mononuclear copper-oxygen mediated C–H and O–H activations: A comparison between biological and synthetic systems. CHINESE JOURNAL OF CATALYSIS 2022. [DOI: 10.1016/s1872-2067(21)63974-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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4
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Copper monooxygenase reactivity: Do consensus mechanisms accurately reflect experimental observations? J Inorg Biochem 2022; 231:111780. [DOI: 10.1016/j.jinorgbio.2022.111780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022]
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5
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Tyminski KS, Stewart SC, Nagorski RW. Carbinol Derivatives of
N
‐(α‐Hydroxybenzyl)benzamide: Acid and Base‐Dependent Kinetics in Water and the Mechanistic Implications for Carbinolamide Reactivity. ChemistrySelect 2021. [DOI: 10.1002/slct.202102816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kurt S. Tyminski
- Department of Chemistry Illinois State University Box 4160 Normal IL USA 61790-4160
| | - Sarah C. Stewart
- Department of Chemistry Illinois State University Box 4160 Normal IL USA 61790-4160
| | - Richard W. Nagorski
- Department of Chemistry Illinois State University Box 4160 Normal IL USA 61790-4160
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6
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Wu P, Fan F, Song J, Peng W, Liu J, Li C, Cao Z, Wang B. Theory Demonstrated a "Coupled" Mechanism for O 2 Activation and Substrate Hydroxylation by Binuclear Copper Monooxygenases. J Am Chem Soc 2019; 141:19776-19789. [PMID: 31746191 DOI: 10.1021/jacs.9b09172] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Multiscale simulations have been performed to address the longstanding issue of "dioxygen activation" by the binuclear copper monooxygenases (PHM and DβM), which have been traditionally classified as "noncoupled" binuclear copper enzymes. Our QM/MM calculations rule out that CuM(II)-O2• is an active species for H-abstraction from the substrate. In contrast, CuM(II)-O2• would abstract an H atom from the cosubstrate ascorbate to form a CuM(II)-OOH intermediate in PHM and DβM. Consistent with the recently reported structural features of DβM, the umbrella sampling shows that the "open" conformation of the CuM(II)-OOH intermediate could readily transform into the "closed" conformation in PHM, in which we located a mixed-valent μ-hydroperoxodicopper(I,II) intermediate, (μ-OOH)Cu(I)Cu(II). The subsequent O-O cleavage and OH moiety migration to CuH generate the unexpected species (μ-O•)(μ-OH)Cu(II)Cu(II), which is revealed to be the reactive intermediate responsible for substrate hydroxylation. We also demonstrate that the flexible Met ligand is favorable for O-O cleavage reactions, while the replacement of Met with the strongly bound His ligand would inhibit the O-O cleavage reactivity. As such, the study not only demonstrates a "coupled" mechanism for O2 activation by binuclear copper monooxygenases but also deciphers the full catalytic cycle of PHM and DβM in accord with the available experimental data. These findings of O2 activation and substrate hydroxylation by binuclear copper monooxygenases could expand our understanding of the reactivities of the synthetic monocopper complexes.
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Affiliation(s)
- Peng Wu
- State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , People's Republic of China.,University of Chinese Academy of Sciences , Beijing 100049 , People's Republic of China
| | - Fangfang Fan
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , People's Republic of China
| | - Jinshuai Song
- College of Chemistry, and Institute of Green Catalysis , Zhengzhou University , Zhengzhou 450001 , People's Republic of China
| | - Wei Peng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , People's Republic of China
| | - Jia Liu
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , People's Republic of China
| | - Chunsen Li
- State Key Laboratory of Structural Chemistry , Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou , Fujian 350002 , People's Republic of China.,Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry , Xiamen , Fujian 361005 , People's Republic of China
| | - Zexing Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , People's Republic of China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , People's Republic of China
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7
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Chauhan S, Hosseinzadeh P, Lu Y, Blackburn NJ. Stopped-Flow Studies of the Reduction of the Copper Centers Suggest a Bifurcated Electron Transfer Pathway in Peptidylglycine Monooxygenase. Biochemistry 2016; 55:2008-21. [PMID: 26982589 DOI: 10.1021/acs.biochem.6b00061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidylglycine monooxygenase (PHM) is a dicopper enzyme that plays a vital role in the amidation of glycine-extended pro-peptides. One of the crucial aspects of its chemistry is the transfer of two electrons from an electron-storing and -transferring site (CuH) to the oxygen binding site and catalytic center (CuM) over a distance of 11 Å during one catalytic turnover event. Here we present our studies of the first electron transfer (ET) step (reductive phase) in wild-type (WT) PHM as well as its variants. Stopped flow was used to record the reduction kinetic traces using the chromophoric agent N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) as the reductant. The reduction was found to be biphasic in the WT PHM with an initial fast phase (17.2 s(-1)) followed by a much slower phase (0.46 s(-1)). We were able to ascribe the fast and slow phase to the CuH and CuM sites, respectively, by making use of the H242A and H107AH108A mutants that contain only the CuH site and CuM site, respectively. In the absence of substrate, the redox potentials determined by cyclic voltammetry were 270 mV (CuH site) and -15 mV (CuM site), but binding of substrate (Ac-YVG) was found to alter both potentials so that they converged to a common value of 83 mV. Substrate binding also accelerated the slow reductive phase by ~10-fold, an effect that could be explained at least partially by the equalization of the reduction potential of the copper centers. Studies of H108A showed that the ET to the CuM site is blocked, highlighting the role of the H108 ligand as a component of the reductive ET pathway. Strikingly, the rate of reduction of the H172A variant was unaffected despite the rate of catalysis being 3 orders of magnitude slower than that of the WT PHM. These studies strongly indicate that the reductive phase and catalytic phase ET pathways are different and suggest a bifurcated ET pathway in PHM. We propose that H172 and Y79 form part of an alternate pathway for the catalytic phase ET while the H108 ligand along with the water molecules and substrate form the reductive phase ET pathway.
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Affiliation(s)
- Shefali Chauhan
- Institute of Environmental Health, Oregon Health and Science University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
| | - Parisa Hosseinzadeh
- Department of Chemistry and Biochemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Yi Lu
- Department of Chemistry and Biochemistry, University of Illinois at Urbana-Champaign , 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Ninian J Blackburn
- Institute of Environmental Health, Oregon Health and Science University , 3181 Southwest Sam Jackson Park Road, Portland, Oregon 97239, United States
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Abad E, Rommel JB, Kästner J. Reaction mechanism of the bicopper enzyme peptidylglycine α-hydroxylating monooxygenase. J Biol Chem 2014; 289:13726-38. [PMID: 24668808 DOI: 10.1074/jbc.m114.558494] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peptidylglycine α-hydroxylating monooxygenase is a noninteracting bicopper enzyme that stereospecifically hydroxylates the terminal glycine of small peptides for its later amidation. Neuroendocrine messengers, such as oxytocin, rely on the biological activity of this enzyme. Each catalytic turnover requires one oxygen molecule, two protons from the solvent, and two electrons. Despite this enzyme having been widely studied, a consensus on the reaction mechanism has not yet been found. Experiments and theoretical studies favor a pro-S abstraction of a hydrogen atom followed by the rebinding of an OH group. However, several hydrogen-abstracting species have been postulated; because two protons are consumed during the reaction, several protonation states are available. An electron transfer between the copper atoms could play a crucial role for the catalysis as well. This leads to six possible abstracting species. In this study, we compare them on equal footing. We perform quantum mechanics/molecular mechanics calculations, considering the glycine hydrogen abstraction. Our results suggest that the most likely mechanism is a protonation of the abstracting species before the hydrogen abstraction and another protonation as well as a reduction before OH rebinding.
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Affiliation(s)
- Enrique Abad
- From the Computational Biochemistry Group, Institute of Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Judith B Rommel
- From the Computational Biochemistry Group, Institute of Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
| | - Johannes Kästner
- From the Computational Biochemistry Group, Institute of Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
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9
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Abstract
Peptide hormones with a C-terminal amide regulate numerous physiological processes and are associated with many disease states. Consequently, the key enzymes involved in their production, peptidylglycine α-amidating monooxygenase and carboxypeptidase E, have been studied intensively. This review surveys what is known about the enzymes themselves and their cofactors, as well as their substrates and competitive and mechanism-based inhibitors.
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10
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Wong MT, Choi SB, Kuan CS, Chua SL, Chang CH, Normi YM, Too WCS, Wahab HA, Few LL. Structural modeling and biochemical characterization of recombinant KPN_02809, a zinc-dependent metalloprotease from Klebsiella pneumoniae MGH 78578. Int J Mol Sci 2012; 13:901-917. [PMID: 22312293 PMCID: PMC3269727 DOI: 10.3390/ijms13010901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 12/29/2011] [Accepted: 01/09/2012] [Indexed: 11/16/2022] Open
Abstract
Klebsiella pneumoniae is a Gram-negative, cylindrical rod shaped opportunistic pathogen that is found in the environment as well as existing as a normal flora in mammalian mucosal surfaces such as the mouth, skin, and intestines. Clinically it is the most important member of the family of Enterobacteriaceae that causes neonatal sepsis and nosocomial infections. In this work, a combination of protein sequence analysis, structural modeling and molecular docking simulation approaches were employed to provide an understanding of the possible functions and characteristics of a hypothetical protein (KPN_02809) from K. pneumoniae MGH 78578. The computational analyses showed that this protein was a metalloprotease with zinc binding motif, HEXXH. To verify this result, a ypfJ gene which encodes for this hypothetical protein was cloned from K. pneumoniae MGH 78578 and the protein was overexpressed in Escherichia coli BL21 (DE3). The purified protein was about 32 kDa and showed maximum protease activity at 30 °C and pH 8.0. The enzyme activity was inhibited by metalloprotease inhibitors such as EDTA, 1,10-phenanthroline and reducing agent, 1,4-dithiothreitol (DTT). Each molecule of KPN_02809 protein was also shown to bind one zinc ion. Hence, for the first time, we experimentally confirmed that KPN_02809 is an active enzyme with zinc metalloprotease activity.
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Affiliation(s)
- Mun Teng Wong
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
| | - Sy Bing Choi
- Pharmaceutical Design and Simulation (PhDS) Laboratory, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden 11800, Pulau Pinang, Malaysia; E-Mail:
| | - Chee Sian Kuan
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
| | - Siang Ling Chua
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
| | - Chiat Han Chang
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
| | - Yahaya Mohd Normi
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia; E-Mail:
| | - Wei Cun See Too
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
| | - Habibah A. Wahab
- Pharmaceutical Design and Simulation (PhDS) Laboratory, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden 11800, Pulau Pinang, Malaysia; E-Mail:
- Authors to whom correspondence should be addressed; E-Mails: (H.A.W.); (L.L.F.); Tel.: +604-6532238 (H.A.W.); +609-7677536 (L.L.F.); Fax: +604-6570017 (H.A.W.); +609-7677515 (L.L.F.)
| | - Ling Ling Few
- School of Health Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian 16150, Kelantan, Malaysia; E-Mails: (M.T.W.); (C.S.K.); (S.L.C.); (C.H.C.); (W.C.S.T.)
- Authors to whom correspondence should be addressed; E-Mails: (H.A.W.); (L.L.F.); Tel.: +604-6532238 (H.A.W.); +609-7677536 (L.L.F.); Fax: +604-6570017 (H.A.W.); +609-7677515 (L.L.F.)
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11
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McIntyre NR, Lowe EW, Belof JL, Ivkovic M, Shafer J, Space B, Merkler DJ. Evidence for substrate preorganization in the peptidylglycine α-amidating monooxygenase reaction describing the contribution of ground state structure to hydrogen tunneling. J Am Chem Soc 2010; 132:16393-402. [PMID: 21043511 DOI: 10.1021/ja1019194] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Peptidylglycine α-amidating monooxygenase (PAM) is a bifunctional enzyme which catalyzes the post-translational modification of inactive C-terminal glycine-extended peptide precursors to the corresponding bioactive α-amidated peptide hormone. This conversion involves two sequential reactions both of which are catalyzed by the separate catalytic domains of PAM. The first step, the copper-, ascorbate-, and O(2)-dependent stereospecific hydroxylation at the α-carbon of the C-terminal glycine, is catalyzed by peptidylglycine α-hydroxylating monooxygenase (PHM). The second step, the zinc-dependent dealkylation of the carbinolamide intermediate, is catalyzed by peptidylglycine amidoglycolate lyase. Quantum mechanical tunneling dominates PHM-dependent C(α)-H bond activation. This study probes the substrate structure dependence of this chemistry using a set of N-acylglycine substrates of varying hydrophobicity. Primary deuterium kinetic isotope effects (KIEs), molecular mechanical docking, alchemical free energy perturbation, and equilibrium molecular dynamics were used to study the role played by ground-state substrate structure on PHM catalysis. Our data show that all Ν-acylglycines bind sequentially to PHM in an equilibrium-ordered fashion. The primary deuterium KIE displays a linear decrease with respect to acyl chain length for straight-chain N-acylglycine substrates. Docking orientation of these substrates displayed increased dissociation energy proportional to hydrophobic pocket interaction. The decrease in KIE with hydrophobicity was attributed to a preorganization event which decreased reorganization energy by decreasing the conformational sampling associated with ground state substrate binding. This is the first example of preorganization in the family of noncoupled copper monooxygenases.
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Affiliation(s)
- Neil R McIntyre
- Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States
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Takahashi K, Harada S, Higashimoto Y, Shimokawa C, Sato H, Sugishima M, Kaida Y, Noguchi M. Involvement of Metals in Enzymatic and Nonenzymatic Decomposition of C-Terminal α-Hydroxyglycine to Amide: An Implication for the Catalytic Role of Enzyme-Bound Zinc in the Peptidylamidoglycolate Lyase Reaction. Biochemistry 2009; 48:1654-62. [DOI: 10.1021/bi8018866] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kenichi Takahashi
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Saori Harada
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Yuichiro Higashimoto
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Chizu Shimokawa
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Hideaki Sato
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Yasuhiko Kaida
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
| | - Masato Noguchi
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan, and Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology, Tosu 841-0052, Japan
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Merkler DJ, Asser AS, Baumgart LE, Carballo N, Carpenter SE, Chew GH, Cosner CC, Dusi J, Galloway LC, Lowe AB, Lowe EW, King L, Kendig RD, Kline PC, Malka R, Merkler KA, McIntyre NR, Romero M, Wilcox BJ, Owen TC. Substituted hippurates and hippurate analogs as substrates and inhibitors of peptidylglycine alpha-hydroxylating monooxygenase (PHM). Bioorg Med Chem 2008; 16:10061-74. [PMID: 18952446 DOI: 10.1016/j.bmc.2008.10.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2008] [Revised: 10/03/2008] [Accepted: 10/04/2008] [Indexed: 10/21/2022]
Abstract
Peptidyl alpha-hydroxylating monooxygenase (PHM) functions in vivo towards the biosynthesis of alpha-amidated peptide hormones in mammals and insects. PHM is a potential target for the development of inhibitors as drugs for the treatment of human disease and as insecticides for the management of insect pests. We show here that relatively simple ground state analogs of the PHM substrate hippuric acid (C(6)H(5)-CO-NH-CH(2)-COOH) inhibit the enzyme with K(i) values as low as 0.5microM. Substitution of sulfur atom(s) into the hippuric acid analog increases the affinity of PHM for the inhibitor. Replacement of the acetylglycine moiety, -CO-NH-CH(2)-COOH with an S-(thioacetyl)thioglycolic acid moiety, -CS-S-CH(2)-COOH, yields compounds with the highest PHM affinity. Both S-(2-phenylthioacetyl)thioglycolate and S-(4-ethylthiobenzoyl)thioglycolic acid inhibit the proliferation of cultured human prostate cancer cells at concentrations >100-fold excess of their respective K(i) values. Comparison of K(i) values between mammalian PHM and insect PHM shows differences in potency suggesting that a PHM-based insecticide with limited human toxicity can be developed.
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Affiliation(s)
- David J Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA.
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De M, Bell J, Blackburn NJ, Mains RE, Eipper BA. Role for an essential tyrosine in peptide amidation. J Biol Chem 2006; 281:20873-20882. [PMID: 16704972 DOI: 10.1074/jbc.m513886200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The catalytic core of the peptidyl-alpha-hydroxyglycine alpha-amidating lyase (PAL) domain of peptidylglycine alpha-amidating monooxygenase was investigated with respect to its ability to function as a ureidoglycolate lyase and the identity and role of its bound metal ions. The purified PAL catalytic core (PALcc) contains molar equivalents of calcium and zinc along with substoichiometric amounts of iron and functions as a ureidoglycolate lyase. Limiting iron availability in the cells synthesizing PALcc reduces the specific activity of the enzyme produced. Concentrated samples of native PALcc have an absorption maximum at 560 nm, suggestive of a phenolate-Fe(III) charge transfer complex. An essential role for a Tyr residue was confirmed by elimination of PAL activity following site-directed mutagenesis. Purified PALcc in which the only conserved Tyr residue (Tyr(654)) was mutated to Phe was secreted normally, but was catalytically inactive and lacked bound iron and bound zinc. Our data demonstrate an essential role for Tyr(654) and suggest that it serves as an Fe(III) ligand in an essential iron-zinc bimetallic site.
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Affiliation(s)
- Mithu De
- Neuroscience Department, University of Connecticut Health Center, Farmington, Connecticut 06030-3401
| | - Joseph Bell
- Neuroscience Department, University of Connecticut Health Center, Farmington, Connecticut 06030-3401
| | - Ninian J Blackburn
- Neuroscience Department, University of Connecticut Health Center, Farmington, Connecticut 06030-3401
| | - Richard E Mains
- Neuroscience Department, University of Connecticut Health Center, Farmington, Connecticut 06030-3401
| | - Betty A Eipper
- Neuroscience Department, University of Connecticut Health Center, Farmington, Connecticut 06030-3401.
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16
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Chew GH, Galloway LC, McIntyre NR, Schroder LA, Richards KM, Miller SA, Wright DW, Merkler DJ. Ubiquitin and ubiquitin-derived peptides as substrates for peptidylglycine alpha-amidating monooxygenase. FEBS Lett 2005; 579:4678-84. [PMID: 16098968 DOI: 10.1016/j.febslet.2005.06.089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 06/15/2005] [Accepted: 06/18/2005] [Indexed: 12/16/2022]
Abstract
Ubiquitin (Ub) and the ubiquitin-like proteins (UBLs) mediate an array of cellular functions. These proteins contain a C-terminal glycine residue that is key to their function. Oxidative conversion of C-terminal glycine-extended prohormones to the corresponding alpha-amidated peptide is one step in the biosynthesis of bioactive peptide hormones. The enzyme catalyzing this reaction is peptidylglycine alpha-amidating monooxygenase (PAM). We report herein that Ub is a PAM substrate with a (V/K)(amidation) that is similar to other known peptide substrates. This work is significant because PAM and the UBLs co-localize to the hypothalamus and the adrenal medulla and are both over-expressed in glioblastomas.
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Affiliation(s)
- Geoffrey H Chew
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., SCA 400, Tampa, FL 33620-5250, USA
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Mennenga AG, Johnson AL, Nagorski RW. General-buffer catalysis of the reaction of N-(hydroxymethyl)benzamide: a new pathway for the aqueous reaction of carbinolamides. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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El Meskini R, Culotta VC, Mains RE, Eipper BA. Supplying copper to the cuproenzyme peptidylglycine alpha-amidating monooxygenase. J Biol Chem 2003; 278:12278-84. [PMID: 12529325 DOI: 10.1074/jbc.m211413200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
We explored the role of known copper transporters and chaperones in delivering copper to peptidylglycine-alpha-hydroxylating monooxygenase (PHM), a copper-dependent enzyme that functions in the secretory pathway lumen. We examined the roles of yeast Ccc2, a P-type ATPase related to human ATP7A (Menkes disease protein) and ATP7B (Wilson disease protein), as well as yeast Atx1, a cytosolic copper chaperone. We expressed soluble PHMcc (catalytic core) in yeast using the yeast pre-pro-alpha-mating factor leader region to target the enzyme to the secretory pathway. Although the yeast genome encodes no PHM-like enzyme, PHMcc expressed in yeast is at least as active as PHMcc produced by mammalian cells. PHMcc partially co-migrated with a Golgi marker during subcellular fractionation and partially co-localized with Ccc2 based on immunofluorescence. To determine whether production of active PHM was dependent on copper trafficking pathways involving the CCC2 or ATX1 genes, we expressed PHMcc in wild-type, ccc2, and atx1 mutant yeast. Although ccc2 and atx1 mutant yeast produce normal levels of PHMcc protein, it lacks catalytic activity. Addition of exogenous copper yields fully active PHMcc. Similarly, production of active PHM in mouse fibroblasts is impaired in the presence of a mutant ATP7A gene. Although delivery of copper to lumenal cuproproteins like PAM involves ATP7A, lumenal chaperones may not be required.
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Affiliation(s)
- Rajaâ El Meskini
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut 06030-3401, USA
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Satani M, Takahashi K, Sakamoto H, Harada S, Kaida Y, Noguchi M. Expression and characterization of human bifunctional peptidylglycine alpha-amidating monooxygenase. Protein Expr Purif 2003; 28:293-302. [PMID: 12699694 DOI: 10.1016/s1046-5928(02)00684-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report the purification and characterization of human bifunctional peptidylglycine alpha-amidating monooxygenase (the bifunctional PAM) expressed in Chinese hamster ovary cells. PAM is in charge of the formation of the C-terminal amides of biologically active peptides. The bifunctional PAM possesses two catalytic domains in a single polypeptide, peptidylglycine alpha-hydroxylating monooxygenase (PHM, EC 1.14.17.3) and peptidylamidoglycolate lyase (PAL, EC 4.3.2.5). By introducing a stop codon at 835 Glu, we were able to eliminate the membrane-spanning domain in the C-terminal region and succeeded in purifying a soluble form of bifunctional PAM that was secreted into the medium. Through a three-step purification procedure, we obtained 0.3mg of the purified PAM, which showed a single band at 91 kDa on SDS-PAGE, from 1L of monolayer culture medium. Metals contained in the purified PAM were analyzed and chemical modifications were performed to gain insight into the mechanism of the PAL reaction. Inductively coupled plasma detected 0.62 mol of Zn(2+) and 1.25 mol of Cu(2+) per mol of bifunctional PAM. Further, the addition of 1mM EDTA reduced the PAL activity by about 50%, but the decreased activity was recovered by the addition of an excess amount of Zn(2+). In a series of chemical modifications, phenylglyoxal almost completely eliminated the PAL activity and diethyl pyrocarbonate suppressed activity by more than 70%. These findings implied that Arg and His residues might play crucial roles during catalysis.
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Affiliation(s)
- Manabu Satani
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
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