1
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Si H, Du D, Jiao C, Sun Y, Li L, Tang B. Biomimetic synergistic effect of redox site and Lewis acid for construction of efficient artificial enzyme. Nat Commun 2024; 15:6315. [PMID: 39060279 PMCID: PMC11282276 DOI: 10.1038/s41467-024-50687-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Accepted: 07/18/2024] [Indexed: 07/28/2024] Open
Abstract
In enzymatic catalysis, the redox site and Lewis acid are the two main roles played by metal to assist amino acids. However, the reported enzyme mimics only focus on the redox-active metal as redox site, while the redox-inert metal as Lewis acid has, to the best of our knowledge, not been studied, presenting a bottleneck of enzyme mimics construction. Based on this, a series of highly efficient MxV2O5·nH2O peroxidase mimics with vanadium as redox site and alkaline-earth metal ion (M2+) as Lewis acid are reported. Experimental results and theoretical calculations indicate the peroxidase-mimicking activity of MxV2O5·nH2O show a periodic change with the Lewis acidity (ion potential) of M2+, revealing the mechanism of redox-inert M2+ regulating electron transfer of V-O through non-covalent polarization and thus promoting H2O2 adsorbate dissociation. The biomimetic synergetic effect of redox site and Lewis acid is expected to provide an inspiration for design of enzyme mimics.
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Affiliation(s)
- Haibin Si
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China
| | - Dexin Du
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China
| | - Chengcheng Jiao
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China
| | - Yan Sun
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China
| | - Lu Li
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China.
- Jinan Institute of Quantum Technology, Jinan, 250101, P. R. China.
| | - Bo Tang
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, Jinan, 250014, P. R. China.
- Laoshan Laboratory, Qingdao, 266237, P. R. China.
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2
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Singh PK, Pandey S, Rani C, Ahmad N, Viswanathan V, Sharma P, Kaur P, Sharma S, Singh TP. Potassium-induced partial inhibition of lactoperoxidase: structure of the complex of lactoperoxidase with potassium ion at 2.20 Å resolution. J Biol Inorg Chem 2021; 26:149-159. [PMID: 33427997 DOI: 10.1007/s00775-020-01844-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022]
Abstract
Lactoperoxidase, a heme-containing glycoprotein, catalyzes the oxidation of thiocyanate by hydrogen peroxide into hypothiocyanite which acts as an antibacterial agent. The prosthetic heme moiety is attached to the protein through two ester linkages via Glu258 and Asp108. In lactoperoxidase, the substrate-binding site is formed on the distal heme side. To study the effect of physiologically important potassium ion on the structure and function of lactoperoxidase, the fresh protein samples were isolated from yak (Bos grunniens) colostrum and purified to homogeneity. The biochemical studies with potassium fluoride showed a significant reduction in the catalytic activity. Lactoperoxidase was crystallized using 200 mM ammonium nitrate and 20% PEG-3350 at pH 6.0. The crystals of LPO were soaked in the solution of potassium fluoride and used for the X-ray intensity data collection. Structure determination at 2.20 Å resolution revealed the presence of a potassium ion in the distal heme cavity. Structure determination further revealed that the propionic chain attached to pyrrole ring C of the heme moiety, was disordered into two components each having an occupancy of 0.5. One component occupied a position similar to the normally observed position of propionic chain while the second component was found in the distal heme cavity. The potassium ion in the distal heme cavity formed five coordinate bonds with two oxygen atoms of propionic moiety, Nε2 atom of His109 and two oxygen atoms of water molecules. The presence of potassium ion in the distal heme cavity hampered the catalytic activity of lactoperoxidase.
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Affiliation(s)
- Prashant K Singh
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Sadanand Pandey
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Chitra Rani
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Nayeem Ahmad
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - V Viswanathan
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Pradeep Sharma
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Punit Kaur
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Sujata Sharma
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India
| | - Tej P Singh
- Department of Biophysics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110 029, India.
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3
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Nnamchi CI, Parkin G, Efimov I, Basran J, Kwon H, Svistunenko DA, Agirre J, Okolo BN, Moneke A, Nwanguma BC, Moody PCE, Raven EL. Structural and spectroscopic characterisation of a heme peroxidase from sorghum. J Biol Inorg Chem 2015; 21:63-70. [PMID: 26666777 PMCID: PMC4771821 DOI: 10.1007/s00775-015-1313-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/05/2015] [Indexed: 10/28/2022]
Abstract
A cationic class III peroxidase from Sorghum bicolor was purified to homogeneity. The enzyme contains a high-spin heme, as evidenced by UV-visible spectroscopy and EPR. Steady state oxidation of guaiacol was demonstrated and the enzyme was shown to have higher activity in the presence of calcium ions. A Fe(III)/Fe(II) reduction potential of -266 mV vs NHE was determined. Stopped-flow experiments with H2O2 showed formation of a typical peroxidase Compound I species, which converts to Compound II in the presence of calcium. A crystal structure of the enzyme is reported, the first for a sorghum peroxidase. The structure reveals an active site that is analogous to those for other class I heme peroxidase, and a substrate binding site (assigned as arising from binding of indole-3-acetic acid) at the γ-heme edge. Metal binding sites are observed in the structure on the distal (assigned as a Na(+) ion) and proximal (assigned as a Ca(2+)) sides of the heme, which is consistent with the Ca(2+)-dependence of the steady state and pre-steady state kinetics. It is probably the case that the structural integrity (and, thus, the catalytic activity) of the sorghum enzyme is dependent on metal ion incorporation at these positions.
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Affiliation(s)
| | - Gary Parkin
- Department of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Igor Efimov
- Department of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Jaswir Basran
- Department of Molecular and Cell Biology, Henry Wellcome Laboratory for Structural Biology, University of Leicester, Lancaster Road, Leicester, LE1 9HN, UK
| | - Hanna Kwon
- Department of Molecular and Cell Biology, Henry Wellcome Laboratory for Structural Biology, University of Leicester, Lancaster Road, Leicester, LE1 9HN, UK
| | - Dimitri A Svistunenko
- School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
| | - Jon Agirre
- York Structural Biology Laboratory, Department of Chemistry, The University of York, Heslington, York, YO10 5DD, UK
| | | | - Anene Moneke
- Department of Microbiology, University of Nigeria, Nsukka, Nigeria
| | | | - Peter C E Moody
- Department of Molecular and Cell Biology, Henry Wellcome Laboratory for Structural Biology, University of Leicester, Lancaster Road, Leicester, LE1 9HN, UK
| | - Emma L Raven
- Department of Chemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK.
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4
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Gorjanović S. A Review: Biological and Technological Functions of Barley Seed Pathogenesis-Related Proteins (PRs). JOURNAL OF THE INSTITUTE OF BREWING 2012. [DOI: 10.1002/j.2050-0416.2009.tb00389.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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5
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Substrate specificity of the Chamaerops excelsa palm tree peroxidase. A steady-state kinetic study. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.molcatb.2011.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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6
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Zamorano LS, Cuadrado NH, Galende PP, Roig MG, Shnyrov VL. Steady-state kinetics of <i>Roystonea regia</i> palm tree peroxidase. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/jbpc.2012.31002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Shoresh M, Spivak M, Bernstein N. Involvement of calcium-mediated effects on ROS metabolism in the regulation of growth improvement under salinity. Free Radic Biol Med 2011; 51:1221-34. [PMID: 21466848 DOI: 10.1016/j.freeradbiomed.2011.03.036] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Revised: 03/19/2011] [Accepted: 03/28/2011] [Indexed: 10/18/2022]
Abstract
Salinity reduces Ca(2+) availability, transport, and mobility to growing regions of the plant and supplemental Ca(2+) is known to reduce salinity damages. This study was undertaken to unravel some of the ameliorative mechanisms of Ca(2+) on salt stress at the cellular and tissue levels. Zea mays L. plants were grown in nutrient solution containing 1 or 80 mM NaCl with various Ca(2+) levels. Measurements of growth and physiological parameters, such as ion imbalance, indicated that the Ca(2+)-induced alleviation mechanisms differed between plant organs. Under salinity, H(2)O(2) levels increased in the leaf-growing tissue with increasing levels of supplemental Ca(2+) and reached the levels of control plants, whereas superoxide levels remained low at all Ca(2+) levels, indicating that Ca(2+) affected growth by increasing H(2)O(2) but not superoxide levels. Salinity completely abolished apoplastic peroxidase activity. Supplemental Ca(2+) increased its activity only slightly. However, under salinity, polyamine oxidase (PAO) activity was shifted toward the leaf base probably as an adaptive mechanism aimed at restoring normal levels of reactive oxygen species (ROS) at the expansion zone where NADPH oxidase could no longer provide the required ROS for growth. Interestingly, addition of Ca(2+) shifted the PAO-activity peak back to its original location in addition to its enhancement. The increase in PAO activity in conjunction with low levels of apoplastic peroxidase is supportive of cellular growth via nonenzymatic wall loosening derived by the increase in H(2)O(2) and less supportive of the peroxidase-mediated cross-linking of wall material. Thus extracellular Ca(2+) can modulate ROS levels at specific tissue localization and developmental stages thereby affecting cellular extension.
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Affiliation(s)
- Michal Shoresh
- Institute of Soil, Water, and Environmental Sciences, Agricultural Research Organization, The Volcani Center, Bet-Dagan 50–250, Israel
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8
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Pintus F, Mura A, Bellelli A, Arcovito A, Spanò D, Pintus A, Floris G, Medda R. Allosteric modulation of Euphorbia peroxidase by nickel ions. FEBS J 2008; 275:1201-12. [DOI: 10.1111/j.1742-4658.2008.06280.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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Dicko MH, Gruppen H, Hilhorst R, Voragen AGJ, van Berkel WJH. Biochemical characterization of the major sorghum grain peroxidase. FEBS J 2006; 273:2293-307. [PMID: 16650004 DOI: 10.1111/j.1742-4658.2006.05243.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The major cationic peroxidase in sorghum grain (SPC4) , which is ubiquitously present in all sorghum varieties was purified to apparent homogeneity, and found to be a highly basic protein (pI approximately 11). MS analysis showed that SPC4 consists of two glycoforms with molecular masses of 34,227 and 35,629 Da and it contains a type-b heme. Chemical deglycosylation allowed to estimate sugar contents of 3.0% and 6.7% (w/w) in glycoform I and II, respectively, and a mass of the apoprotein of 33,246 Da. High performance anion exchange chromatography allowed to determine the carbohydrate constituents of the polysaccharide chains. The N-terminal sequence of SPC4 is not blocked by pyroglutamate. MS analysis showed that six peptides, including the N-terminal sequence of SPC4 matched with the predicted tryptic peptides of gene indice TC102191 of sorghum chromosome 1, indicating that TC102191 codes for the N-terminal part of the sequence of SPC4, including a signal peptide of 31 amino acids. The N-terminal fragment of SPC4 (213 amino acids) has a high sequence identity with barley BP1 (85%), rice Prx23 (90%), wheat WSP1 (82%) and maize peroxidase (58%), indicative for a common ancestor. SPC4 is activated by calcium ions. Ca2+ binding increased the protein conformational stability by raising the melting temperature (Tm) from 67 to 82 degrees C. SPC4 catalyzed the oxidation of a wide range of aromatic substrates, being catalytically more efficient with hydroxycinnamates than with tyrosine derivatives. In spite of the conserved active sites, SPC4 differs from BP1 in being active with aromatic compounds above pH 5.
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Affiliation(s)
- Mamoudou H Dicko
- Laboratory of Biochemistry, Department of Agrotechnology and Food Sciences, Wageningen University, The Netherlands.
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10
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Hiner ANP, Sidrach L, Chazarra S, Varón R, Tudela J, García-Cánovas F, Rodríguez-López JN. Kinetic study of the effects of calcium ions on cationic artichoke (Cynara scolymus L.) peroxidase: calcium binding, steady-state kinetics and reactions with hydrogen peroxide. Biochimie 2004; 86:667-76. [PMID: 15556277 DOI: 10.1016/j.biochi.2004.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Accepted: 09/10/2004] [Indexed: 11/24/2022]
Abstract
The apparent catalytic constant (k(cat)) of artichoke (Cynara scolymus L.) peroxidase (AKPC) with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) increased 130-fold in the presence of calcium ions (Ca2+) but the affinity (K(m)) of the enzyme for ABTS was 500 times lower than for Ca2+-free AKPC. AKPC is known to exhibit an equilibrium between 6-aquo hexa-coordinate and penta-coordinate forms of the haem iron that is modulated by Ca2+ and affects compound I formation. Measurements of the Ca2+ dissociation constant (K(D)) were complicated by the water-association/dissociation equilibrium yielding a global value more than 1000 times too high. The value for the Ca2+ binding step alone has now been determined to be K(D) approximately 10 nM. AKPC-Ca2+ was more resistant to inactivation by hydrogen peroxide (H(2)O(2)) and exhibited increased catalase activity. An analysis of the complex H(2)O(2) concentration dependent kinetics of Ca2+-free AKPC is presented.
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Affiliation(s)
- Alexander N P Hiner
- GENZ: Grupo de Investigacíon de Enzimología, Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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11
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Carvalho ASL, Santos AM, Neves-Petersen MT, Petersen SB, Aires-Barros MR, e Melo EP. Conformational states of HRPA1 induced by thermal unfolding: Effect of low molecular weight solutes. Biopolymers 2004; 75:173-86. [PMID: 15356871 DOI: 10.1002/bip.20100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fluorescence, CD, and activity measurements were used to characterize the different conformational states of horseradish peroxidase A1 induced by thermal unfolding. Picosecond time-resolved fluorescence studies showed a three-exponential decay dominated by a picosecond lifetime component resulting from energy transfer from tryptophan to heme. Upon thermal unfolding a decrease in the preexponential factor of the picosecond lifetime and an increase in the quantum yield were observed approaching the characteristics observed for apoHRPA1. The fraction of heme-quenched fluorophore decreased to 0.4 after unfolding as shown by acrylamide quenching. A new unfolding pathway for HRPA1 was proposed and the effect of the low molecular weight solutes trehalose, sorbitol, and melezitose on this pathway was analyzed. Native HRPA1 unfolds with an intermediate between the native and the unfolded conformation. The unfolded conformation can refold to the native state or to a native-like conformation with no calcium ions upon cooling or can give an irreversible denatured state. The refolded conformation with no calcium ions was clearly identified in a second thermal scan in the presence of EDTA and shows secondary and tertiary structures, heme reincorporation in the cavity, and at least 59% of activity. Melezitose stabilized the refolded Ca2+-depleted protein and induced a more complex mechanism for heme disruption. The effect of sorbitol and trehalose were mainly characterized by an increase in the temperature of unfolding.
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Affiliation(s)
- Ana Sofia L Carvalho
- Centro de Engenharia Biológica e Química, Instituto Superior Técnico, Av. Rovisco Pais 1049-001, Lisboa, Portugal
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12
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Hiner ANP, Sidrach L, Chazarra S, Varón R, Tudela J, García-Cánovas F, Rodríguez-López JN. Compound I formation in artichoke (Cynara scolymus L.) peroxidase is modulated by the equilibrium between pentacoordinated and 6-aquo hexacoordinated forms of the heme and by calcium ions. Biochemistry 2003; 42:8799-808. [PMID: 12873141 DOI: 10.1021/bi034580z] [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: 11/29/2022]
Abstract
Basic artichoke (Cynara scolymus L.) peroxidase (AKP-C), when purified from the plant, has an unusually intense and sharp Soret absorption peak. The resonance Raman spectrum [López-Molina, D., et al. (2003) J. Inorg. Biochem. 94, 243-254] suggested a mixture of pentacoordinate high-spin (5cHS) and 6-aquo hexacoordinate high-spin (6cHS) ferric heme species. The rate constant (k(1)) of compound I formation with hydrogen peroxide (H(2)O(2)) was also lower than expected. Further stopped-flow studies have shown this reaction to be biphasic: a nonsaturating fast phase and a slow phase with complex H(2)O(2) concentration dependence. Addition of calcium ions (Ca(2+)) changed the absorption spectrum, suggesting the formation of a fully 5cHS species with a k(1) more than 5 orders of magnitude greater than that in the absence of Ca(2+) using the chelator ethylenediaminetetraacetic acid. Ca(2+) titrations gave a dissociation constant for a single Ca(2+) of approximately 20 microM. The circular dichroism spectrum of AKP-C was not significantly altered by Ca(2+), indicating that any structural changes will be minor, but removal of Ca(2+) did suppress the alkaline transition between pH 10 and 11. A kinetic analysis of the reaction of Ca(2+)-free AKP-C with H(2)O(2) supports an equilibrium between a slow-reacting 6cHS form and a more rapidly reacting 5cHS species, the presence of which was confirmed in nonaqueous solution. AKP-C, as purified, is a mixture of Ca(2+)-bound 5cHS, 6-aquo 6cHS, and Ca(2+)-free 5cHS species. The possibility that Ca(2+) concentration could control peroxidase activity in the plant is discussed.
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Affiliation(s)
- Alexander N P Hiner
- Grupo de Enzimología (GENZ), Departamento de Bioquímica y Biología Molecular-A, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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13
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Lee A, Kirichenko A, Vygodina T, Siletsky SA, Das TK, Rousseau DL, Gennis R, Konstantinov AA. Ca(2+)-binding site in Rhodobacter sphaeroides cytochrome C oxidase. Biochemistry 2002; 41:8886-98. [PMID: 12102631 DOI: 10.1021/bi020183x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cytochrome c oxidase (COX) from R. sphaeroides contains one Ca(2+) ion per enzyme that is not removed by dialysis versus EGTA. This is similar to COX from Paracoccus denitrificans [Pfitzner, U., Kirichenko, A., Konstantinov, A. A., Mertens, M., Wittershagen, A., Kolbesen, B. O., Steffens, G. C. M., Harrenga, A., Michel, H., and Ludwig, B. (1999) FEBS Lett. 456, 365-369] and is in contrast to the bovine oxidase, which binds Ca(2+) reversibly. A series of R. sphaeroides mutants with replacements of the E54, Q61, and D485 residues, which form the Ca(2+) coordination sphere in subunit I, has been generated. The substitutions for the E54 residue do not assemble normally. Mutants with the Q61 replacements are active and retain the tightly bound Ca(2+); their spectra are not perturbed by added Ca(2+) or EGTA. The D485A mutant is active, binds to Ca(2+) reversibly, like the mitochondrial oxidase, and exhibits the red shift in the heme a absorption spectrum upon Ca(2+) binding for both reduced and oxidized states of heme a. The K(d) value of 6 nM determined by equilibrium titrations is much lower than that reported for the homologous D477A mutant of Paracoccus denitrificans or for bovine COX (K(d) = 1-3 microM). The rate of Ca(2+) binding with the D485A oxidase (k(on) = 5 x 10(3) M(-1) s(-1)) is comparable to that observed earlier for bovine COX, but the off-rate is extremely slow (approximately 10(-3) s(-1)) and highly temperature-dependent. The k(off) /k(on) ratio (190 nM) is about 30-fold higher than the equilibrium K(d) of 6 nM, indicating that formation of the Ca(2+)-adduct may involve more than one step. Sodium ions reverse the Ca(2+)-induced red shift of heme a and dramatically decrease the rate of Ca(2+) binding to the D485A mutant COX. With the D485A mutant, 1 Ca(2+) competes with 1 Na(+) for the binding site, whereas 2 Na(+) compete with 1 Ca(2+) for binding to the bovine oxidase. This finding indicates that the aspartic residue D442 (a homologue of R. sphaeroides D485) may be the second Na(+) binding site in bovine COX. No effect of Ca(2+) binding to the D485A mutant is evident on either the steady-state enzymatic activity or several time-resolved partial steps of the catalytic cycle. It is proposed that the tightly bound Ca(2+) plays a structural role in the bacterial oxidases while the reversible binding with the mammalian enzyme may be involved in the regulation of mitochondrial function.
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Affiliation(s)
- Alex Lee
- Department of Biochemistry, University of Illinois at Urbana-Champaign, 600 S. Goodwin Avenue, Urbana, IL 61801, USA
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14
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Lad L, Mewies M, Basran J, Scrutton NS, Raven EL. Role of histidine 42 in ascorbate peroxidase. Kinetic analysis of the H42A and H42E variants. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3182-92. [PMID: 12084058 DOI: 10.1046/j.1432-1033.2002.02998.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To examine the role of the distal His42 residue in the catalytic mechanism of pea cytosolic ascorbate peroxidase, two site-directed variants were prepared in which His42 was replaced with alanine (H42A) or glutamic acid (H42E). Electronic spectra of the ferric derivatives of H42A and H42E (pH 7.0, mu = 0.10 m, 25.0 degrees C) revealed wavelength maxima [lambda(max) (nm): 397, 509, approximately equal to 540(sh), 644 (H42A); 404, 516, approximately equal to 538(sh), 639 (H42E)] consistent with a predominantly five-co-ordinate high-spin iron. The specific activity of H42E for oxidation of L-ascorbate (8.2 +/- 0.3 U.mg(-1)) was approximately equal to 30-fold lower than that of the recombinant wild-type enzyme (rAPX); the H42A variant was essentially inactive but activity could be partially recovered by addition of exogenous imidazoles. The spectra of the Compound I intermediates of H42A [lambda(max) (nm) = 403, 534, 575(sh), 645] and H42E [lambda(max) (nm) = 404, 530, 573(sh), 654] were similar to those of rAPX. Pre-steady-state data for formation of Compound I for H42A and H42E were consistent with a mechanism involving accumulation of a transient enzyme intermediate (K(d)) followed by conversion of this intermediate into Compound I (k'(1)). Values for k'(1) and K(d) were, respectively, 4.3 +/- 0.2 s(-1) and 30 +/- 2.0 mM (H42A) and 28 +/- 1.0 s(-1) and 0.09 +/- 0.01 mM (H42E). Photodiode array experiments for H42A revealed wavelength maxima for this intermediate at 401 nm, 522 nm and 643 nm, consistent with the formation of a transient [H42A-H(2)O(2)] species. Rate constants for Compound I formation for H42A were independent of pH, but for rAPX and H42E were pH-dependent [pKa = 4.9 +/- 0.1 (rAPX) and pK(a) = 6.7 +/- 0.2 (H42E)]. The results provide: (a) evidence that His42 is critical for Compound I formation in APX; (b) confirmation that titration of His42 controls Compound I formation and an assignment of the pK(a) for this group; (c) mechanistic and spectroscopic evidence for an intermediate before Compound I formation; (d) evidence that a glutamic acid residue at position 42 can act as the acid-base catalyst in ascorbate peroxidase.
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Affiliation(s)
- Latesh Lad
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK
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15
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Nissum M, Schiødt CB, Welinder KG. Reactions of soybean peroxidase and hydrogen peroxide pH 2.4-12.0, and veratryl alcohol at pH 2.4. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1545:339-48. [PMID: 11342058 DOI: 10.1016/s0167-4838(00)00295-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Peroxidase from soybean seed coat (SBP) has properties that makes it particularly suited for practical applications. Therefore, it is essential to know its fundamental enzymatic properties. Stopped-flow techniques were used to investigate the pH dependence of the reaction of SBP and hydrogen peroxide. The reaction is linearly dependent on hydrogen peroxide concentration at acidic and neutral pH with the second order rate constant k(1)=2.0x10(7) M(-1) s(-1), pH 4-8. From pH 9.3 to 10.2 the reaction is biphasic, a novel observation for a peroxidase at alkaline pH. A fast reaction has the characteristics of the reaction at neutral pH, and a slow reaction shows hyperbolic dependence on hydrogen peroxide concentration. At pH >10.5 only the slow reaction is seen. The shift in mechanism is coincident with the change in haem iron co-ordination to a six-coordinate low spin hydroxy ligated alkaline form. The pK(a) value for the alkaline transition was observed at 9.7+/-0.1, 9.6+/-0.1 and 9.9+/-0.2 by spectrophotometric titration, the fast phase amplitude, and decrease in the apparent second order rate constant, respectively. An acidic pK(a) at 3.2+/-0.3 was also determined from the apparent second order rate constant. The reactions of soybean peroxidase compounds I and II with veratryl alcohol at pH 2.44 give very similar second order rate constants, k(2)=(2.5+/-0.1)x10(4) M(-1) s(-1) and k(3)=(2.2+/-0.1)x10(4) M(-1) s(-1), respectively, which is unusual. The electronic absorption spectra of compounds I, II and III at pH 7.07 show characteristic bands at 400 and 651 nm (compound I), 416, 527 and 555 nm (compound II), and 414, 541 and 576 nm (compound III). No additional intermediates were observed.
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Affiliation(s)
- M Nissum
- Department of Protein Chemistry, Institute of Molecular Biology, University of Copenhagen, Denmark
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16
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Blodig W, Smith AT, Doyle WA, Piontek K. Crystal structures of pristine and oxidatively processed lignin peroxidase expressed in Escherichia coli and of the W171F variant that eliminates the redox active tryptophan 171. Implications for the reaction mechanism. J Mol Biol 2001; 305:851-61. [PMID: 11162097 DOI: 10.1006/jmbi.2000.4346] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The heme enzyme lignin peroxidase (LiP) from the white rot fungus Phanerochaete chrysosporium contains a solvent exposed redox active tryptophan residue (Trp171) that carries a unique hydroxy group stereo-specifically attached to its C(beta) atom. A Trp171Phe mutant has no activity at all towards the substrate veratryl alcohol. The mechanism of veratryl alcohol oxidation involving beta-hydroxy-Trp171 is largely unknown. Here, we present the first crystal structures of LiP isozyme H8 at high resolution in its pristine non-hydroxylated form, of the C(beta)-hydroxylated form, and of the Trp171Phe mutant using recombinantly expressed and refolded protein produced from Escherichia coli. As a consequence, all structures are unglycosylated. Structural changes in response to the mutation are marginal and allow us to attribute the complete lack of activity exclusively to the absence of the redox active indole side-chain. The origin of the stereospecificity of the Trp171 hydroxylation can be explained on structural grounds. A reaction mechanism involving Trp171 is proposed and the possible function of the modification is discussed. Another important result regarding the ongoing debate on the co-ordination state of the heme iron in the resting state is that the iron is six co-ordinate in all cases the data being collected at room temperature. The mean distance from the iron to the distal water ligand is 2.18(+/-0.08) A. The radical scavenger orcinol was found to decrease radiation damage to the crystals, during data collection at room temperature.
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Affiliation(s)
- W Blodig
- Institut für Biochemie, Eidgenössische Technische Hochschule (ETH), Universitätstrasse 16, Zürich, CH-8092, Switzerland
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17
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Indiani C, Feis A, Howes BD, Marzocchi MP, Smulevich G. Effect of low temperature on soybean peroxidase: spectroscopic characterization of the quantum-mechanically admixed spin state. J Inorg Biochem 2000; 79:269-74. [PMID: 10830877 DOI: 10.1016/s0162-0134(99)00156-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A spectroscopic study of soybean peroxidase (SBP) has been carried out using electronic absorption, resonance Raman (RR) and electron paramagnetic resonance (EPR) spectroscopy in order to determine the effects of temperature on the heme spin state. Upon lowering the temperature a transition from high spin to low spin is induced in SBP resulting from conformational changes in the heme cavity, including a contraction of the heme core, the reorientation of the vinyl group in position 2 of the porphyrin macrocycle, and the binding of the distal His to the Fe atom. Moreover, the combined analysis of the data derived from the different techniques at both room and low temperatures demonstrates that at low temperature the quantum-mechanically admixed spin state (QS) of SBP has RR frequencies different from those observed for the QS species at room temperature.
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Affiliation(s)
- C Indiani
- Dipartimento di Chimica, Università di Firenze, Italy
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18
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Priori AM, Indiani C, De Sanctis G, Marini S, Santucci R, Smulevich G, Coletta M. Anion- and pH-linked conformational transition in horseradish peroxidase. J Inorg Biochem 2000; 79:25-30. [PMID: 10830843 DOI: 10.1016/s0162-0134(99)00229-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In a previous study we have shown that bringing horseradish peroxidase to pH 3.0 induces a spectroscopic transition (G. Smulevich et al., Biochemistry 36 (1997) 640). We have extended the investigation on this pH-linked conformational change to different experimental conditions, such as (i) in phosphate alone, (ii) in HCl alone and (iii) in phosphate + NaCl. The data obtained allow a number of conclusions to be drawn, namely: (a) the exposure to pH 3.0 under all conditions brings about an alteration of the distal portion of the heme pocket, leading to the rapid formation of a hexa-coordinated species; (b) only in the presence of phosphate is the hexa-coordination followed by a slow cleavage (or severe weakening) of the proximal Fe-His bond, and (c) the rate of this second process is speeded up in the presence of Cl- ions. Such observations underline the presence of a communication pathway between the two opposite sides of the heme pocket, such that any alteration of the structural arrangement on one side of the heme cavity is transmitted to the other, inducing a corresponding conformational change.
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Affiliation(s)
- A M Priori
- Dipartimento di Biologia Molecolare, Cellulare ed Animale, Università di Camerino, Italy
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19
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Abstract
Plants experience a wide array of environmental stimuli, not all of which are favorable, and, unlike animals, are unable to move away from stressful environments. They therefore require a mechanism with which to recognize and respond to abiotic stresses of many different types. Frequently this mechanism involves intracellular calcium. Stress-induced changes in the cytosolic concentration of Ca2+ ([Ca2+]cyt) occur as a result of influx of Ca2+ from outside the cell, or release of Ca2+ from intracellular stores. These alterations in [Ca2+]cyt constitute a signal that is transduced via calmodulin, calcium-dependent protein kinases, and other Ca(2+)-controlled proteins to effect a wide array of downstream responses involved in the protection of the plant and adjustment to the new environmental conditions. Ca2+ signaling has been implicated in plant responses to a number of abiotic stresses including low temperature, osmotic stress, heat, oxidative stress, anoxia, and mechanical perturbation, which are reviewed in this article.
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Affiliation(s)
- H Knight
- Department of Plant Sciences, University of Oxford, United Kingdom.
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BILLAUD CATHERINE, KOHLER BERND, BOIVIN PATRICK, NICOLAS JACQUES. POLYPHENOLIC SUBSTRATES OF CATIONIC AND NEUTRAL/ANIONIC PEROXIDASES FROM BARLEY AND MALT USING A CHRONOMETRIC METHOD FOR THE DETERMINATION OF POD ACTIVITY. J Food Biochem 1999. [DOI: 10.1111/j.1745-4514.1999.tb00035.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Howes BD, Schiodt CB, Welinder KG, Marzocchi MP, Ma JG, Zhang J, Shelnutt JA, Smulevich G. The quantum mixed-spin heme state of barley peroxidase: A paradigm for class III peroxidases. Biophys J 1999; 77:478-92. [PMID: 10388773 PMCID: PMC1300345 DOI: 10.1016/s0006-3495(99)76905-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electronic absorption and resonance Raman (RR) spectra of the ferric form of barley grain peroxidase (BP 1) at various pH values, at both room temperature and 20 K, are reported, together with electron paramagnetic resonance spectra at 10 K. The ferrous forms and the ferric complex with fluoride have also been studied. A quantum mechanically mixed-spin (QS) state has been identified. The QS heme species coexists with 6- and 5-cHS hemes; the relative populations of these three spin states are found to be dependent on pH and temperature. However, the QS species remains in all cases the dominant heme spin species. Barley peroxidase appears to be further characterized by a splitting of the two vinyl stretching modes, indicating that the vinyl groups are differently conjugated with the porphyrin. An analysis of the currently available spectroscopic data for proteins from all three peroxidase classes suggests that the simultaneous occurrence of the QS heme state as well as the splitting of the two vinyl stretching modes is confined to class III enzymes. The former point is discussed in terms of the possible influences of heme deformations on heme spin state. It is found that moderate saddling alone is probably not enough to cause the QS state, although some saddling may be necessary for the QS state.
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Affiliation(s)
- B D Howes
- Dipartimento di Chimica, Università di Firenze, 50121 Firenze, Italy
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Neri F, Indiani C, Baldi B, Vind J, Welinder KG, Smulevich G. Role of the distal phenylalanine 54 on the structure, stability, and ligand binding of Coprinus cinereus peroxidase. Biochemistry 1999; 38:7819-27. [PMID: 10387022 DOI: 10.1021/bi982811+] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Resonance Raman and electronic absorption spectra obtained at various pH values for the Fe3+ form of distal F54 mutants of Coprinus cinereus peroxidase are reported, together with the Fe2+ form and fluoride and imidazole adducts at pH 6.0, 5.0, and 10.5, respectively. The distal phenylalanine residue has been replaced by the small aliphatic residues glycine and valine and the hydrogen-bonding aromatic residues tyrosine and tryptophan (F54G, -V, -Y, and -W, respectively). These mutations resulted in transitions between ferric high-spin five-coordinate and six-coordinate forms, and caused a decrease of the pKa of the alkaline transition together with a higher tendency for unfolding. The mutations also alter the ability of the proteins to bind fluoride in such a way that those that are six-coordinate at pH 5.0 bind more strongly than both wild-type CIP and F54Y which are five-coordinate at this pH value. The data provide evidence that the architecture of the distal pocket of CIP is altered by the mutations. Direct evidence is provided that the distal phenylalanine plays an important role in controlling the conjugation between the vinyl double bonds and the porphyrin macrocycle, as indicated by the reorientation of the vinyl groups upon mutation of phenylalanine with the small aliphatic side chains of glycine and valine residues. Furthermore, it appears that the presence of the hydrogen-bonding tyrosine or tryptophan in the cavity increases the pKa of the distal histidine for protonation compared with that of wild-type CIP.
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Affiliation(s)
- F Neri
- Dipartimento di Chimica, Universita' di Firenze, Italy
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Teilum K, Ostergaard L, Welinder KG. Disulfide bond formation and folding of plant peroxidases expressed as inclusion body protein in Escherichia coli thioredoxin reductase negative strains. Protein Expr Purif 1999; 15:77-82. [PMID: 10024473 DOI: 10.1006/prep.1998.0985] [Citation(s) in RCA: 16] [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
Escherichia coli is widely used for the production of proteins, which are of interest in structure and function studies. The folding yield of inclusion body protein is, however, generally low (a few percent) for proteins such as the plant and fungal peroxidases, which contain four disulfide bonds, two Ca2+ ions, and a heme group. We have studied the expression yield and folding efficiency of (i) a novel Arabidopsis thaliana peroxidase, ATP N; and (ii) barley grain peroxidase, BP 1. The expression yield ranges from 0 to 60 microgram/ml of cell culture depending on the peroxidase gene and the vector/host combination. The choice of E. coli strain in particular affects the yield of active peroxidase obtained in the folding step. Thus, the yield of active ATP N peroxidase can be increased 50-fold by using thioredoxin reductase negative strains, which facilitate the formation of disulfide bonds in inclusion body protein.
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Affiliation(s)
- K Teilum
- Institute of Molecular Biology, University of Copenhagen, Oster Farimagsgade 2A, Copenhagen K, DK-1353, Denmark
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Abstract
Peroxidase-catalysed reactions are being analysed at an increasingly advanced level of structural and mechanistic sophistication. A significant development in this respect has been the long-anticipated solution of crystal structures for several plant peroxidases and a fungal peroxidase complexed to benzhydroxamic acid. New insights into peroxide binding and catalysis have been obtained through site-directed mutagenesis, a technique also crucial to recent progress in understanding the diversity of substrate interaction sites associated with peroxidases from different sources.
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Affiliation(s)
- A T Smith
- School of Biological Sciences, University of Sussex, Brighton, BN1 9QG, UK.
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Henriksen A, Welinder KG, Gajhede M. Structure of barley grain peroxidase refined at 1.9-A resolution. A plant peroxidase reversibly inactivated at neutral pH. J Biol Chem 1998; 273:2241-8. [PMID: 9442067 DOI: 10.1074/jbc.273.4.2241] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The crystal structure of the major peroxidase of barley grain (BP 1) has been solved by molecular replacement and phase combination and refined to an R-factor of 19.2% for all data between 38 and 1.9 A. The refined model includes amino acid residues 1-309, one calcium ion, one sodium ion, iron-protoporphyrin IX, and 146 solvent molecules. BP 1 has the apparently unique property of being unable to catalyze the reaction with the primary substrate hydrogen peroxide to form compound I at pH values > 5, a feature investigated by obtaining crystal structure data at pH 5.5, 7.5, and 8.5. Structural comparison shows that the overall fold of inactive barley grain peroxidase at these pH values resembles that of both horseradish peroxidase C and peanut peroxidase. The key differences between the structures of active horseradish peroxidase C and inactive BP 1 include the orientation of the catalytic distal histidine, disruption of a hydrogen bond between this histidine and a conserved asparagine, and apparent substitution of calcium at the distal cation binding site with sodium at pH 7.5. These profound changes are a result of a dramatic structural rearrangement to the loop region between helices B and C. This is the first time that structural rearrangements linked to active site chemistry have been observed by crystallography in the peroxidase domain distal to heme.
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Affiliation(s)
- A Henriksen
- Department of Physical Chemistry, University of Copenhagen, København O, Denmark.
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