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Pitsawong W, Chenprakhon P, Dhammaraj T, Medhanavyn D, Sucharitakul J, Tongsook C, van Berkel WJH, Chaiyen P, Miller AF. Tuning of p Ka values activates substrates in flavin-dependent aromatic hydroxylases. J Biol Chem 2020; 295:3965-3981. [PMID: 32014994 DOI: 10.1074/jbc.ra119.011884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/29/2020] [Indexed: 12/31/2022] Open
Abstract
Hydroxylation of substituted phenols by flavin-dependent monooxygenases is the first step of their biotransformation in various microorganisms. The reaction is thought to proceed via electrophilic aromatic substitution, catalyzed by enzymatic deprotonation of substrate, in single-component hydroxylases that use flavin as a cofactor (group A). However, two-component hydroxylases (group D), which use reduced flavin as a co-substrate, are less amenable to spectroscopic investigation. Herein, we employed 19F NMR in conjunction with fluorinated substrate analogs to directly measure pKa values and to monitor protein events in hydroxylase active sites. We found that the single-component monooxygenase 3-hydroxybenzoate 6-hydroxylase (3HB6H) depresses the pKa of the bound substrate analog 4-fluoro-3-hydroxybenzoate (4F3HB) by 1.6 pH units, consistent with previously proposed mechanisms. 19F NMR was applied anaerobically to the two-component monooxygenase 4-hydroxyphenylacetate 3-hydroxylase (HPAH), revealing depression of the pKa of 3-fluoro-4-hydroxyphenylacetate by 2.5 pH units upon binding to the C2 component of HPAH. 19F NMR also revealed a pKa of 8.7 ± 0.05 that we attributed to an active-site residue involved in deprotonating bound substrate, and assigned to His-120 based on studies of protein variants. Thus, in both types of hydroxylases, we confirmed that binding favors the phenolate form of substrate. The 9 and 14 kJ/mol magnitudes of the effects for 3HB6H and HPAH-C2, respectively, are consistent with pKa tuning by one or more H-bonding interactions. Our implementation of 19F NMR in anaerobic samples is applicable to other two-component flavin-dependent hydroxylases and promises to expand our understanding of their catalytic mechanisms.
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Affiliation(s)
- Warintra Pitsawong
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom 73170, Thailand
| | - Taweesak Dhammaraj
- Faculty of Pharmacy, Mahasarakham University, Maha Sarakham 44150, Thailand
| | - Dheeradhach Medhanavyn
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Jeerus Sucharitakul
- Department of Biochemistry, Faculty of Dentistry, Chulalongkorn University, Bangkok 10300, Thailand
| | - Chanakan Tongsook
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom 73000, Thailand
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University and Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan Valley, 555 Moo 1 Payupnai, Wangchan, Rayong 21210, Thailand
| | - Anne-Frances Miller
- Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055
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Moriwaki Y, Yato M, Terada T, Saito S, Nukui N, Iwasaki T, Nishi T, Kawaguchi Y, Okamoto K, Arakawa T, Yamada C, Fushinobu S, Shimizu K. Understanding the Molecular Mechanism Underlying the High Catalytic Activity of p-Hydroxybenzoate Hydroxylase Mutants for Producing Gallic Acid. Biochemistry 2019; 58:4543-4558. [DOI: 10.1021/acs.biochem.9b00443] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Yoshitaka Moriwaki
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | | | - Tohru Terada
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Seiji Saito
- Department of Medical Management and Informatics, Hokkaido Information University, 59-2, Nishi Nopporo, Ebetsu, Hokkaido 069-8585, Japan
- Genaris, Inc., 75-1 Ono-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0046, Japan
| | - Noriyuki Nukui
- Genaris, Inc., 75-1 Ono-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0046, Japan
| | - Takumi Iwasaki
- Genaris, Inc., 75-1 Ono-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0046, Japan
| | - Tatsunari Nishi
- Genaris, Inc., 75-1 Ono-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0046, Japan
| | - Yuko Kawaguchi
- Department of Biochemistry and Molecular Biology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8602, Japan
| | - Ken Okamoto
- Department of Biochemistry and Molecular Biology, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8602, Japan
| | - Takatoshi Arakawa
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Chihaya Yamada
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shinya Fushinobu
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kentaro Shimizu
- The Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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3
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Giridharan SSP, Caplan S. MICAL-family proteins: Complex regulators of the actin cytoskeleton. Antioxid Redox Signal 2014; 20:2059-73. [PMID: 23834433 PMCID: PMC3993057 DOI: 10.1089/ars.2013.5487] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
SIGNIFICANCE The molecules interacting with CasL (MICAL) family members participate in a multitude of activities, including axonal growth cone repulsion, membrane trafficking, apoptosis, and bristle development in flies. An interesting feature of MICAL proteins is the presence of an N-terminal flavo-mono-oxygenase domain. This mono-oxygenase domain generates redox potential with which MICALs can either oxidize proteins or produce reactive oxygen species (ROS). Actin is one such protein that is affected by MICAL function, leading to dramatic cytoskeletal rearrangements. This review describes the MICAL-family members, and discusses their mechanisms of actin-binding and regulation of actin cytoskeleton organization. RECENT ADVANCES Recent studies show that MICALs directly induce oxidation of actin molecules, leading to actin depolymerization. ROS production by MICALs also causes oxidation of collapsin response mediator protein-2, a microtubule assembly promoter, which subsequently undergoes phosphorylation. CRITICAL ISSUES MICAL proteins oxidize proteins through two mechanisms: either directly by oxidizing methionine residues or indirectly via the production of ROS. It remains unclear whether MICAL proteins employ both mechanisms or whether the activity of MICAL-family proteins might vary with different substrates. FUTURE DIRECTIONS The identification of additional substrates oxidized by MICAL will shed new light on MICAL protein function. Additional directions include expanding studies toward the MICAL-like homologs that lack flavin adenine dinucleotide domains and oxidation activity.
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Affiliation(s)
- Sai Srinivas Panapakkam Giridharan
- Department of Biochemistry and Molecular Biology, and the Pamela and Fred Buffett Cancer Center, University of Nebraska Medical Center , Omaha, Nebraska
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Montersino S, Tischler D, Gassner GT, van Berkel WJH. Catalytic and Structural Features of Flavoprotein Hydroxylases and Epoxidases. Adv Synth Catal 2011. [DOI: 10.1002/adsc.201100384] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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Control of catalysis in flavin-dependent monooxygenases. Arch Biochem Biophys 2010; 493:26-36. [DOI: 10.1016/j.abb.2009.11.028] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 11/17/2009] [Accepted: 11/17/2009] [Indexed: 11/17/2022]
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6
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Nakamura T, Motoyama T, Hirono S, Yamaguchi I. Identification, characterization, and site-directed mutagenesis of recombinant pentachlorophenol 4-monooxygenase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2004; 1700:151-9. [PMID: 15262224 DOI: 10.1016/j.bbapap.2004.04.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2003] [Revised: 04/07/2004] [Accepted: 04/13/2004] [Indexed: 11/25/2022]
Abstract
In a previous study, we constructed a three-dimensional (3D) structure of pentachlorophenol 4-monooxygenase (PcpB). In this study, further analyses are performed to examine the important amino acid residues in the catalytic reaction by identification of the proteins with mass spectrometry, circular dichroism (CD) and UV spectrometry, and determination of kinetic parameters. Recombinant histidine-tagged PcpB protein was produced and shown to have a similar activity to the native protein. Mutant proteins of PcpB were then produced (F85A, Y216A, Y216F, R235A, R235E, R235K, Y397A and Y397F) on the basis of the proposed 3D structure. The CD spectra of the proteins showed that there were no major changes in the structures of the mutant proteins, with the exception of R235E. Steady-state kinetics showed a 20-fold reduction in k(cat)/K(m) and a ninefold increase in K(m) for Y216F and a threefold reduction in k(cat)/K(m) and a sixfold increase in K(m) for Y397F compared to the wild type. On the other hand, the value of k(cat)/K(m) of R235K mutant was the same as that of wild type. As a result, it was confirmed that Y216 and Y397 play an important role with respect to the recognition of the substrate.
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Affiliation(s)
- Takashi Nakamura
- Laboratory for Remediation Research, Environmental Plant Research Group, Plant Science Center, RIKEN Institute, 1-7-22 Suehiro, Tsurumi, Yokohama City, Kanagawa 230-0045, Japan.
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Moonen M, Fraaije M, Rietjens I, Laane C, van Berkel W. Flavoenzyme-Catalyzed Oxygenations and Oxidations of Phenolic Compounds. Adv Synth Catal 2002. [DOI: 10.1002/1615-4169(200212)344:10<1023::aid-adsc1023>3.0.co;2-t] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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8
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van der Bolt FJ, Vervoort J, van Berkel WJ. Flavin motion in p-hydroxybenzoate hydroxylase. Substrate and effector specificity of the Tyr22-->Ala mutant. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 237:592-600. [PMID: 8647102 DOI: 10.1111/j.1432-1033.1996.0592p.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The side chain of Tyr222 in p-hydroxybenzoate hydroxylase interacts with the carboxy moiety of the substrate. Studies on the Tyr222-->Phe mutant, [F222]p-hydroxybenzoate hydroxylase, have shown that disruption of this interaction hampers the hydroxylation of 4-hydroxybenzoate. Tyr222 is possibly involved in flavin motion, which may facilitate the exchange of substrate and product during catalysis. To elucidate the function of Tyr222 in more detail, in the present study the substrate and effector specificity of the Tyr222-->Ala mutant, [A222]p-hydroxybenzoate hydroxylase, was investigated. Replacement of Tyr222 by Ala impairs the binding of the physiological substrate 4-hydroxybenzoate and the substrate analog 4-aminobenzoate. With these compounds, [A222]p-hydroxybenzoate hydroxylase mainly acts as a NADPH oxidase. [A222]p-hydroxybenzoate hydroxylase tightly interacts with 2,4-dihydroxybenzoate and 2-hydroxy-4-aminobenzoate. Crystallographic data [Schreuder, H.A., Mattevi, A., Oblomova, G., Kalk, K.H., Hol, W.G.J., van der Bolt, F.J.T. & van Berkel, W.J.H. (1994) Biochemistry 33, 10161-10170] suggest that this is due to motion of the flavin ring out of the active site, allowing hydrogen-bond interaction between the 2-hydroxy group of the substrate analogs and N3 of the flavin. [A222]p-Hydroxybenzoate hydroxylase produces about 0.6 mol 2,3,4-trihydroxybenzoate from 2,4-dihydroxybenzoate/mol NADPH oxidized. This indicates that reduction of the Tyr222-->Ala mutant shifts the equilibrium of flavin conformers towards the productive "in' position. [A222]p-Hydroxybenzoate hydroxylase converts 2-fluoro-4-hydroxybenzoate to 2-fluoro-3,4-dihydroxybenzoate. The regioselectivity of hydroxylation suggests that [A222]p-hydroxybenzoate hydroxylase binds the fluorinated substrate in the same orientation as wild-type. Spectral studies suggest that wild-type and [A222]p-hydroxybenzoate hydroxylase bind 2-fluoro-4-hydroxybenzoate in the phenolate form with the flavin ring preferring the "out' conformation. Despite activation of the fluorinated substrate and in contrast to the wild-type enzyme, [A222]p-hydroxybenzoate hydroxylase largely produces hydrogen peroxide. The effector specificity of p-hydroxybenzoate hydroxylase is not changed by the Tyr222-->Ala replacement. This supports the idea that the effector specificity is mainly dictated by the protein-substrate interactions at the re-side of the flavin ring.
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Affiliation(s)
- F J van der Bolt
- Department of Biochemistry, Wageningen Agricultural University, The Netherlands
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9
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Eppink MH, Schreuder HA, Van Berkel WJ. Structure and function of mutant Arg44Lys of 4-hydroxybenzoate hydroxylase implications for NADPH binding. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 231:157-65. [PMID: 7628466 DOI: 10.1111/j.1432-1033.1995.0157f.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Arg44, located at the si-face side of the flavin ring in 4-hydroxybenzoate hydroxylase, was changed to lysine by site-specific mutagenesis. Crystals of [R44K]4-hydroxybenzoate hydroxylase complexed with 4-hydroxybenzoate diffract to 0.22-nm resolution. The structure of [R44K]4-hydroxybenzoate hydroxylase is identical to the wild-type enzyme except for local changes in the vicinity of the mutation. The peptide unit between Ile43 and Lys44 is flipped by about 180 degrees in 50% of the molecules. The phi, psi angles in both the native and flipped conformation are outside the allowed regions and indicate a strained conformation. [R44K]4-Hydroxybenzoate hydroxylase has a decreased affinity for the flavin prosthetic group. This is ascribed to the lost interactions between the side chain of Arg44 and the diphosphoribose moiety of the FAD. The replacement of Arg44 by Lys does not change the position of the flavin ring which occupies the same interior position as in wild type. [R44K]4-Hydroxybenzoate hydroxylase fully couples flavin reduction to substrate hydroxylation. Stopped-flow kinetics showed that the effector role of 4-hydroxybenzoate is largely conserved in the mutant. Replacement of Arg44 by Lys however affects NADPH binding, resulting in a low yield of the charge-transfer species between reduced flavin and NADP+. It is inferred from these data that Arg44 is indispensable for optimal catalysis.
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Affiliation(s)
- M H Eppink
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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10
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Wang SP, Chen YP, Ely B. A ferredoxin, designated FdxP, stimulates p-hydroxybenzoate hydroxylase activity in Caulobacter crescentus. J Bacteriol 1995; 177:2908-11. [PMID: 7751304 PMCID: PMC176966 DOI: 10.1128/jb.177.10.2908-2911.1995] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A gene, fdxP, was identified upstream of the rrnA gene in Caulobacter crescentus and shown to encode ferredoxin II (FdII) by insertional inactivation. FdII is homologous to a class of [2Fe-2S] ferredoxins typified by putidaredoxin. Furthermore, reconstitution assays demonstrated that FdII was able to promote p-hydroxybenzoate hydroxylase activity in ferredoxin-depleted extracts. Thus, biodegradation of p-hydroxybenzoate may be ferredoxin dependent in C. crescentus.
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Affiliation(s)
- S P Wang
- Department of Biological Sciences, University of South Carolina, Columbia 29208, USA
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11
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van Berkel WJ, Eppink MH, Schreuder HA. Crystal structure of p-hydroxybenzoate hydroxylase reconstituted with the modified FAD present in alcohol oxidase from methylotrophic yeasts: evidence for an arabinoflavin. Protein Sci 1994; 3:2245-53. [PMID: 7756982 PMCID: PMC2142777 DOI: 10.1002/pro.5560031210] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The flavin prosthetic group (FAD) of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens was replaced by a stereochemical analog, which is spontaneously formed from natural FAD in alcohol oxidases from methylotrophic yeasts. Reconstitution of p-hydroxybenzoate hydroxylase from apoprotein and modified FAD is a rapid process complete within seconds. Crystals of the enzyme-substrate complex of modified FAD-containing p-hydroxybenzoate hydroxylase diffract to 2.1 A resolution. The crystal structure provides direct evidence for the presence of an arabityl sugar chain in the modified form of FAD. The isoalloxazine ring of the arabinoflavin adenine dinucleotide (a-FAD) is located in a cleft outside the active site as recently observed in several other p-hydroxybenzoate hydroxylase complexes. Like the native enzyme, a-FAD-containing p-hydroxybenzoate hydroxylase preferentially binds the phenolate form of the substrate (pKo = 7.2). The substrate acts as an effector highly stimulating the rate of enzyme reduction by NADPH (kred > 500 s-1). The oxidative part of the catalytic cycle of a-FAD-containing p-hydroxybenzoate hydroxylase differs from native enzyme. Partial uncoupling of hydroxylation results in the formation of about 0.3 mol of 3,4-dihydroxybenzoate and 0.7 mol of hydrogen peroxide per mol NADPH oxidized. It is proposed that flavin motion in p-hydroxybenzoate hydroxylase is important for efficient reduction and that the flavin "out" conformation is associated with the oxidase activity.
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Affiliation(s)
- W J van Berkel
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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12
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Schreuder HA, Mattevi A, Obmolova G, Kalk KH, Hol WG, van der Bolt FJ, van Berkel WJ. Crystal structures of wild-type p-hydroxybenzoate hydroxylase complexed with 4-aminobenzoate,2,4-dihydroxybenzoate, and 2-hydroxy-4-aminobenzoate and of the Tyr222Ala mutant complexed with 2-hydroxy-4-aminobenzoate. Evidence for a proton channel and a new binding mode of the flavin ring. Biochemistry 1994; 33:10161-70. [PMID: 7520279 DOI: 10.1021/bi00199a044] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The crystal structures of wild-type p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens, complexed with the substrate analogues 4-aminobenzoate, 2,4-dihydroxybenzoate, and 2-hydroxy-4-aminobenzoate have been determined at 2.3-, 2.5-, and 2.8-A resolution, respectively. In addition, the crystal structure of a Tyr222Ala mutant, complexed with 2-hydroxy-4-aminobenzoate, has been determined at 2.7-A resolution. The structures have been refined to R factors between 14.5% and 15.8% for data between 8.0 A and the high-resolution limit. The differences between these complexes and the wild-type enzyme-substrate complex are all concentrated in the active site region. Binding of substrate analogues bearing a 4-amino group (4-aminobenzoate and 2-hydroxy-4-aminobenzoate) leads to binding of a water molecule next to the active site Tyr385. As a result, a continuous hydrogen-bonding network is present between the 4-amino group of the substrate analogue and the side chain of His72. It is likely that this hydrogen-bonding network is transiently present during normal catalysis, where it may or may not function as a proton channel assisting the deprotonation of the 4-hydroxyl group of the normal substrate upon binding to the active site. Binding of substrate analogues bearing a hydroxyl group at the 2-position (2,4-dihydroxybenzoate and 2-hydroxy-4-aminobenzoate) leads to displacement of the flavin ring from the active site. The flavin is no longer in the active site (the "in" conformation) but is in the cleft leading to the active site instead (the "out" conformation). It is proposed that movement of the FAD out of the active site may provide an entrance for the substrate to enter the active site and an exit for the product to leave.
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Affiliation(s)
- H A Schreuder
- Bioson Research Institute, University of Groningen, The Netherlands
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Eschrich K, van der Bolt FJ, de Kok A, van Berkel WJ. Role of Tyr201 and Tyr385 in substrate activation by p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 216:137-46. [PMID: 8365400 DOI: 10.1111/j.1432-1033.1993.tb18125.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The crystal structure of the enzyme-substrate complex of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens shows that the hydroxyl group of 4-hydroxybenzoate interacts with the side chain of Tyr201, which is in close contact with the side chain of Tyr385. The role of this hydrogen bonding network in substrate activation was studied by kinetic and spectral analysis of Tyr-->Phe mutant enzymes. The catalytic properties of the enzymes with Tyr201 or Tyr385 replaced by Phe (Tyr201-->Phe and Tyr385-->Phe) with the physiological substrate are comparable with those of the corresponding mutant proteins of p-hydroxybenzoate hydroxylase from P. aeruginosa [Entsch, B., Palfey, B. A., Ballou, D. P. & Massey, V. (1991) J. Biol. Chem. 266, 17341-17349]. Enzyme Tyr201-->Phe has a high Km for NADPH and produces only 5% of 3,4-dihydroxybenzoate/catalytic cycle. Unlike the wild-type enzyme, the Tyr201-->Phe mutant does not stabilize the phenolate form of 4-hydroxybenzoate. With enzyme Tyr385-->Phe, flavin reduction is rate-limiting and the turnover rate is only 2% of wild type. Despite rather efficient hydroxylation, and deviating from the description of the corresponding P. aeruginosa enzyme, mutant Tyr385-->Phe prefers the binding of the phenolic form of 4-hydroxybenzoate. Studies with substrate analogs show that both tyrosines are important for the fine tuning of the effector specificity. Binding of 4-fluorobenzoate differentially stimulates the stabilization of the 4 alpha-hydroperoxyflavin intermediate. Unlike wild type, both Tyr mutants produce 3,4,5-trihydroxybenzoate from 3,4-dihydroxybenzoate. The affinity of enzyme Tyr201-->Phe for the dianionic substrate 2,3,5,6-tetrafluoro-4-hydroxybenzoate is very low, probably because of repulsion of the substrate phenolate in a more nonpolar microenvironment. In contrast to data reported for p-hydroxybenzoate hydroxylase from P. aeruginosa, binding of the inhibitor 4-hydroxycinnamate to wild-type and mutant proteins is not simply described by binary complex formation. A binding model is presented, including secondary binding of the inhibitor. Enzyme Tyr201-->Phe does not stabilize the phenolate form of the inhibitor. In enzyme Tyr385-->Phe, the phenolic pKa of bound 4-hydroxycinnamate is increased with respect to wild type. It is proposed that Tyr385-->Phe is involved in substrate activation by facilitating the deprotonation of Tyr201.
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Affiliation(s)
- K Eschrich
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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14
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Vervoort J, Rietjens IM, van Berkel WJ, Veeger C. Frontier orbital study on the 4-hydroxybenzoate-3-hydroxylase-dependent activity with benzoate derivatives. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 206:479-84. [PMID: 1597186 DOI: 10.1111/j.1432-1033.1992.tb16950.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Based on molecular orbital computer calculations the present paper provides a new hypothesis for catalytic characteristics of 4-hydroxybenzoate-3-hydroxylase (EC 1.14.13.2). A clear correlation between in kcat for the conversion of a series of 4-hydroxylated substrates and their E(HOMO) leads to the hypothesis that Frontier orbital HOMO characteristics [E(HOMO) and HOMO density on C3] of the substrates are the predominant factor in regulating the fate of a benzoate derivative at the active site of the enzyme. The HOMO characteristics can be used to explain whether a compound will be converted by the enzyme or merely acts as an effector. Furthermore, the hypothesis provides quantitative theoretical support for a catalytic mechanism in which the substrate reacts in its dianionic form and for a mechanism in which the electrophilic attack of the C(4a)-peroxyflavin, or of the hydroxyl radical derived from it, on the benzoate dianion is the rate limiting step in catalysis at pH 8, 25 degrees C. Finally, it is demonstrated that the hypothesis can be used as a basis for the formulation of working hypotheses in future research, investigating the conversion and regioselective orientation of the various possible substrates in the active site of the wild-type 4-hydroxybenzoate-3-hydroxylase, its mutants as well as of various other flavin-dependent aromatic hydroxylases, such as for example 3-hydroxybenzoate-4-hydroxylase (EC 1.14.13.23), 3-hydroxybenzoate-6-hydroxylase (EC 1.14.13.24) and phenol hydroxylase (EC 1.14.13.7).
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Affiliation(s)
- J Vervoort
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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15
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Radjendirane V, Bhat MA, Vaidyanathan CS. Affinity purification and characterization of 2,4-dichlorophenol hydroxylase from Pseudomonas cepacia. Arch Biochem Biophys 1991; 288:169-76. [PMID: 1898014 DOI: 10.1016/0003-9861(91)90180-q] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
2,4-Dichlorophenol hydroxylase, a flavoprotein monooxygenase from Pseudomonas cepacia grown on 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole source of carbon, was purified to homogeneity by a single-step affinity chromatography on 2,4-DCP-Sepharose CL-4B. The enzyme was eluted from the affinity matrix with the substrate 2,4-dichlorophenol. The enzyme has a molecular weight of 275,000 consisting of four identical subunits of molecular weight 69,000 and requires exogenous addition of FAD for its complete catalytic activity. The enzyme required an external electron donor NADPH for hydroxylation of 2,4-dichlorophenol to 3,5-dichlorocatechol. NADPH was preferred over NADH. The enzyme had Km value of 14 microM for 2,4-dichlorophenol, and 100 microM for NADPH. The enzyme activity was significantly inhibited by heavy metal ions like Hg2+ and Zn2+ and showed marked inhibition with thiol reagents. Trichlorophenols inhibited the enzyme competitively. The hydroxylase activity decreased as a function of increasing concentrations of Cibacron blue and Procion red dyes. The apoenzyme prepared showed complete loss of FAD when monitored spectrophotometrically and had no enzymatic activity. The inactive apoenzyme was reconstituted with exogenous FAD which completely restored the enzyme activity.
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Affiliation(s)
- V Radjendirane
- Department of Biochemistry, Indian Institute of Science, Bangalore
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16
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Suzuki K, Ohnishi K. Functional modification of an arginine residue on salicylate hydroxylase. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1040:327-36. [PMID: 2223838 DOI: 10.1016/0167-4838(90)90130-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Salicylate hydroxylase from Pseudomonas putida (EC 1.14.13.1, salicylate, NADH:oxygen oxidoreductase) is an FAD-containing monooxygenase, which catalyzes decarboxylative hydroxylation of salicylate to produce catechol in the presence of NADH and O2. By chemical treatment of the enzyme with dicarbonyl reagents, such as glyoxal, the original oxygenase activity was converted to the salicylate-dependent NADH-dehydrogenase activity with free FAD as electron acceptor. One of twenty arginine residues of this enzyme is concerned with this alteration of activity, as shown by the result of its modification at pH 6.9. This result is further supported by the isolation of one arginine-modified enzyme by chromatographic methods on DEAE-Sephadex, A-50 columns. It exhibits the dehydrogenase activity predominantly. This modified enzyme is spectrophotometrically and electrophoretically characterized by a minute conformational change around the active site, and kinetically by a 7-fold increase in an apparent Km for NADH and a decrease of more than 5-fold in an apparent Km for FAD as electron acceptor, with an apparent Vmax of 22 s-1 for the dehydrogenase activity. Flow kinetics also showed a marked decrease in the rate for oxygenation of the reduced enzyme-salicylate complex from 21 s-1 (native enzyme) to 3.3 s-1 (modified enzyme). These facts suggest that one arginine residue of the enzyme is responsible for the NADH binding site, and chemical modification of one arginine residue of the enzyme induces some conformational change around the active site to alter the catalytic activity from oxygenation to dehydrogenation.
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Affiliation(s)
- K Suzuki
- Department of Chemistry, Faculty of Science, Kanazawa University, Japan
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17
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Rajasekharan S, Rajasekharan R, Vaidyanathan CS. Substrate-mediated purification and characterization of a 3-hydroxybenzoic acid-6-hydroxylase from Micrococcus. Arch Biochem Biophys 1990; 278:21-5. [PMID: 2321959 DOI: 10.1016/0003-9861(90)90225-n] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
3-Hydroxybenzoic acid-6-hydroxylase from Micrococcus sp. was purified to homogeneity in a single step using the substrate-mediated interaction of the enzyme with blue-Sepharose. The enzyme was bound to the affinity matrix in the presence of 3-hydroxybenzoic acid and was eluted in its absence. The molecular weight of the purified enzyme is 70,000 with no subunit structure. The flavoenzyme required the exogenous addition of FAD for its complete activity and had a strict preference for NADH over NADPH. The activity of the enzyme was drastically inhibited by Cu2+ and Hg2+ and the inhibition was reversed by thiol reagents.
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Affiliation(s)
- S Rajasekharan
- Department of Biochemistry, Indian Institute of Science, Bangalore
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18
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Schreuder HA, Hol WG, Drenth J. Analysis of the active site of the flavoprotein p-hydroxybenzoate hydroxylase and some ideas with respect to its reaction mechanism. Biochemistry 1990; 29:3101-8. [PMID: 2337581 DOI: 10.1021/bi00464a029] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The flavoprotein p-hydroxybenzoate hydroxylase has been studied extensively by biochemical techniques by others and in our laboratory by X-ray crystallography. As a result of the latter investigations, well-refined crystal structures are known of the enzyme complexed (i) with its substrate p-hydroxybenzoate and (ii) with its reaction product 3,4-dihydroxybenzoate and (iii) the enzyme with reduced FAD. Knowledge of these structures and the availability of the three-dimensional structure of a model compound for the reactive flavin 4a-hydroperoxide intermediate has allowed a detailed analysis of the reaction with oxygen. In the model of this reaction intermediate, fitted to the active site of p-hydroxybenzoate hydroxylase, all possible positions of the distal oxygen were surveyed by rotating this oxygen about the single bond between the C4a and the proximal oxygen. It was found that the distal oxygen is free to sweep an arc of about 180 degrees in the active site. The flavin 4a-peroxide anion, which is formed after reaction of molecular oxygen with reduced FAD, might accept a proton from an active-site water molecule or from the hydroxyl group of the substrate. The position of the oxygen to be transferred with respect to the substrate appears to be almost ideal for nucleophilic attack of the substrate onto this oxygen. The oxygen is situated above the 3-position of the substrate where the substitution takes place, at an angle of about 60 degrees with the aromatic plane, allowing strong interactions with the pi electrons of the substrate. Polarization of the peroxide oxygen-oxygen bond by the enzyme may enhance the reactivity of flavin 4a-peroxide.
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Affiliation(s)
- H A Schreuder
- Laboratory of Chemical Physics, Groningen, The Netherlands
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19
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Van Berkel WJ, Müller F. The temperature and pH dependence of some properties of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens. EUROPEAN JOURNAL OF BIOCHEMISTRY 1989; 179:307-14. [PMID: 2492939 DOI: 10.1111/j.1432-1033.1989.tb14556.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The free and complexed flavoprotein, p-hydroxybenzoate hydroxylase, was studied by light-absorption, circular-dichroism and fluorescence techniques as a function of the pH. The following compounds served as ligands for the enzyme: p-hydroxybenzoate, p-fluorobenzoate, benzoate, p-aminobenzoate and tetrafluoro-p-hydroxybenzoate. Depending on the technique used, the various ligands exhibit pH-dependent physical properties and dissociation constants. The data can be fitted with pKa values in the range 7.7-7.9. It is suggested that this pKa value belongs to a tyrosine residue in the active center of the enzyme. This assignment is supported by published data and additional experiments.
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Affiliation(s)
- W J Van Berkel
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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Wijnands RA, Müller F, Visser AJ. Chemical modification of arginine residues in p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens: a kinetic and fluorescence study. EUROPEAN JOURNAL OF BIOCHEMISTRY 1987; 163:535-44. [PMID: 3104038 DOI: 10.1111/j.1432-1033.1987.tb10901.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The flavoprotein p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens was modified by several arginine-specific reagents. Modifications by 2,3-butanedione led to the loss of activity of the enzyme, but the binding of p-hydroxybenzoate and NADPH to the enzyme was little or not at all affected. However the formation of the enzyme-substrate complex of the modified enzyme was accompanied by an increase of the fluorescence of protein-bound FAD, in contrast to that of native enzyme which leads to quenching of the fluorescence. Enzyme modified by phenylglyoxal did not bind p-hydroxybenzoate nor NADPH. Quantification and protection experiments showed that two arginine residues are essential and a model is described which accounts for the results. Modification by 4-hydroxy-3-nitrophenylglyoxal reduced the affinity of the enzyme for the substrate and NADPH. The ligands offered no protection against inactivation. From this it is concluded that one arginine residue is essential at some stage of the catalysis. This residue is not associated with the substrate- or NADPH-binding site of the enzyme. Time-resolved fluorescence studies showed that the average fluorescence lifetime and the mobility of protein-bound FAD are affected by modification of the enzyme.
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21
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Detmer K, Massey V. Effect of substrate and pH on the oxidative half-reaction of phenol hydroxylase. J Biol Chem 1985. [DOI: 10.1016/s0021-9258(18)88928-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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22
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Wijnands RA, van der Zee J, Van Leeuwen JW, Van Berkel WJ, Müller F. The importance of monopole-monopole and monopole-dipole interactions on the binding of NADPH and NADPH analogues to p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens. Effects of pH and ionic strength. EUROPEAN JOURNAL OF BIOCHEMISTRY 1984; 139:637-44. [PMID: 6421584 DOI: 10.1111/j.1432-1033.1984.tb08051.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
NADPH binding to p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens is found to be strongly dependent on pH and ionic strength. In the ionic strength range of 0.02-0.15 M, optimal NADPH binding is observed at a pH value of 6.4. Extrapolation of the dissociation constants to infinite ionic strength shows that under these conditions optimal binding occurs at pH values greater than 8. Similar results were obtained for complexes between the enzyme and two NADPH analogues in the presence or absence of the substrate. The experimental data can be explained by a theoretical model in which monopole-monopole or monopole-dipole interactions between the enzyme and the ligand are dominant. Changes in the former interaction prevail at low ionic strength and low pH values while the changes in the latter prevail at high ionic strength and high pH values. The dipole moment of the enzyme in the direction of the NADPH binding site was calculated from the ionic strength and pH dependence of the complex formation. The calculated dipole moment of the enzyme is about 2000 Debye at pH 6 and decreases to about 1100 Debye at pH 8.5. The results are discussed with respect to published results, including data obtained from the enzyme from a different source.
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Chen Y, Glenn A, Dilworth M. Uptake and oxidation of aromatic substrates byRhizobium leguminosarumMNF 3841 andRhizobium trifoliiTA1. FEMS Microbiol Lett 1984. [DOI: 10.1111/j.1574-6968.1984.tb00211.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Weijer WJ, Hofsteenge J, Beintema JJ, Wierenga RK, Drenth J. p-Hydroxybenzoate hydroxylase from Pseudomonas fluorescens. 2. Fitting of the amino-acid sequence to the tertiary structure. EUROPEAN JOURNAL OF BIOCHEMISTRY 1983; 133:109-18. [PMID: 6406227 DOI: 10.1111/j.1432-1033.1983.tb07435.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The complete primary and tertiary structure of p-hydroxybenzoate hydroxylase is now known. The amino acid sequences of the two largest CNBr peptides have been fitted to the electron-density map at 0.25-nm resolution. The parts of the polypeptide chain contributing the residues to the FAD-binding site and the residues of the substrate-binding site have been identified. The active site is located in a large hydrophobic area enclosed by all domains of the enzyme structure. Here the substrate, p-hydroxybenzoate, is bound near, but not in direct contact with, the isoalloxazine ring system of FAD. Many side chains from the C-terminal part of the polypeptide chain are involved in subunit-subunit interactions. In the center of one of the largely hydrophobic contact areas between the subunits, a cluster of six aromatic amino acids was found.
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Shoun H, Beppu T. A histidine residue in p-hydroxybenzoate hydroxylase essential for binding of reduced nicotinamide adenine dinucleotide phosphate. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)34794-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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26
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27
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Shoun H, Beppu T, Arima K. An essential arginine residue at the substrate-binding site of p-hydroxybenzoate hydroxylase. J Biol Chem 1980. [DOI: 10.1016/s0021-9258(19)70564-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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28
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May SW, Phillips RS. Protocatechuate 3,4-dioxygenase: implications of ionization effects on binding and dissociation of halohydroxybenzoates and on catalytic turnover. Biochemistry 1979; 18:5933-9. [PMID: 42436 DOI: 10.1021/bi00593a027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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29
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Shoun H, Higashi N, Beppu T, Nakamura S, Hiromi K, Arima K. Studies on the interaction of p-hydroxybenzoate hydroxylase with NADPH. Effects of pH and substrates on the enzyme . NADPH complex formation. J Biol Chem 1979. [DOI: 10.1016/s0021-9258(19)86615-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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