Structural, Spectroscopic, and Reactivity Models for the Manganese Catalases

Wu, Amy J.; Penner‐Hahn, James E.; Pecoraro, Vincent L.

doi:10.1021/cr020627v

Cited by 448 publications

(349 citation statements)

References 207 publications

(420 reference statements)

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“…A noteworthy alternative to the typical field-modulated CW EPR experiment, which also gives absorptive EPR line shapes, is the method of rapid adiabatic passage ( (inhibitors) were bound to the Mn(II) active site of Fosa were correlated to changes in both coordination number as well as the nature of the ligand field. Importantly, this data helped point to a possible molecular mechanism by which FosA helps bacteria subvert the effects of the broad-spectrum antibiotic fosfomycin.Many of the biosystems described above have been modeled by inorganic chemists and EPR spectroscopy serves as an essential tool in the evaluation of the electronic and geometric properties of these synthetic analogues [1,[88][89][90]. In particular, Mn(II):nucleotide adducts and other metal-bound small-molecule constructs (e.g., Mn(II) bound to synthetic RNA) have attracted much attention owing to the involvement of these species in crucial biochemical processes such as ATP hydrolysis [31], R.NA sequence modification [33,91], and cellular signaling.…”

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Multifrequency pulsed EPR studies of biologically relevant manganese(II) complexes

et al. 2007

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Electron paramagnetic resonance studies at multiple frequencies (MF EPR) can provide detailed electronic structure descriptions of unpaired electrons in organic radicals, inorganic complexes, and metalloenzymes. Analysis of these properties aids in the assignment of the chemical environment surrounding the paramagnet and provides mechanistic insight into the chemical reactions in which these systems take part. Herein, we present results from pulsed EPR studies performed at three different frequencies (9, 31, and 130 GHz) on [Mn(II)(H 2 O) 6 ] 2+ , Mn(II) adducts with the nucleotides ATP and GMP, and the Mn(II)-bound form of the hammerhead ribozyme (MnHH). Through line shape analysis and interpretation of the zero-field splitting values derived from successful simulations of the corresponding continuous-wave and field-swept echodetected spectra, these data are used to exemplify the ability of the MF EPR approach in distinguishing the nature of the first ligand sphere. A survey of recent results from pulsed EPR, as well as pulsed electron-nuclear double resonance and electron spin echo envelope modulation spectroscopic studies applied to Mn(II)-dependent systems, is also presented. Mn-Containing Biological SystemsManganese operates as a cofactor in numerous proteins, serving both catalytic and structural roles [1][2][3][4]. Many Mn-dependent enzymes take advantage o f the rich redox chemistry available to the metal, accessing the +2, +3, +4, and perhaps even the +5 oxidation states during their turnover. For example, Mn-superoxide dismutase (MnSOD), which detoxifies the cell of the superoxide radical , cycles between the Mn(II) and Mn(III) oxidation states via the ping-pong type mechanism shown below [5][6][7][8][9].(1a) (1b) Other examples of such mononuclear redox-active enzymes include the manganese peroxidase responsible for lignin degradation by white-rot fungus [10][11][12]; a unique Mndependent form of lipoxygenase [13][14][15][16]; oxalate decarboxylase [17,18]; as well as an extradiol catechol dioxygenase [19][20][21]. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptIn order to help minimize kinetic and thermodynamic penalties associated with electron transfer events and the execution of chemical reactions, two or more metal centers can be coupled together to provide active sites capable of conducting multiple electrons while still operating within a physiologically accessible range of reduction potentials [22]. Only three such examples of redox-active polynuclear Mn enzymes are known: Mn-catalase that disproportionates hydrogen peroxide [23][24][25][26]; a Mn form of ribonucleotide reductase (Mn-RNR) [27,28]; and, arguably the most recognized Mn-dependent enzyme, the photosynthetic core of green plants, algae, and certain cyanobacteria termed photosystem II (PSII) [29,30]. Through a series of photoinitiated electron transfer events, oxidizing equivalents are stored on the tetranuclear Mn core of PSII -the oxygen-evolving complex (OEC) -which then extracts four electr...

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Multifrequency pulsed EPR studies of biologically relevant manganese(II) complexes

et al. 2007

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“…Since XAS accurately reports the structure of metal-protein centers, early workers focused on providing additional high resolution structural and electronic information on crystallographically characterized samples. For instance, XAS enabled detailed structural investigation of metal active sites in imidazolonepropionase 25 , cytochrome P450 26,27 , CO dehydrogenase/acetyl-CoA synthase [28][29][30] , manganese catalases 31,32 , and lipoxygenase 33 by providing key insights into their electronic states and atomic structures. Moreover, insights into the enzymatic reaction mechanisms could be derived from XAS analysis, as was shown for tyrosine hydroxylase 34 , molybdenum(Mo)-nitogenase [35][36][37] , and farnesyltransferase 38 .…”

Section: Application Of Xas In Biologymentioning

confidence: 99%

Application of Stopped-Flow and Time-Resolved X-Ray Absorption Spectroscopy to the Study of Metalloproteins Molecular Mechanisms

Grossman¹,

Sagi²

2012

X-Ray Spectroscopy

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“…Active sites of most of these systems contain manganese ligated mainly by N and O-donor atoms from the amino acid residues of the metalloproteins. Inorganic model complexes have made signi�cant contributions to the progress in delineating the structural and functional aspects of the active sites of these systems [13][14][15][16]. Ligands such as aliphatic, cyclic Schiff bases, polypyridyl systems, and carboxylic acids can stabilize manganese in its various oxidation states [17,18].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Crystal Structure of [MnIII(5-Br-salpn)(D

S¹,

Basheer²,

Shyla³

2013

International Journal of Inorganic Chemistry

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e title compound was synthesized by the reaction between a manganese(II) carboxylate and the tetradentate Schiff base ligand, 5-Br-salpnH 2 [N,N ′ -bis(5-Br-salicylidene)-1,3-diaminopropane] produced in situ. e complex crystallizes in the P2 1 /c space group with unit cell dimensions 12 (10), 12 (10), 2 (3), , 1 2 1 (10), and . e manganese(III) ion is in a distorted octahedral environment with longer axial bonds.

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Structural, Spectroscopic, and Reactivity Models for the Manganese Catalases

Abstract: For Abstract see ChemInform Abstract in Full Text.

Cited by 448 publications

References 207 publications

Multifrequency pulsed EPR studies of biologically relevant manganese(II) complexes

Multifrequency pulsed EPR studies of biologically relevant manganese(II) complexes

Application of Stopped-Flow and Time-Resolved X-Ray Absorption Spectroscopy to the Study of Metalloproteins Molecular Mechanisms

Synthesis and Crystal Structure of [MnIII(5-Br-salpn)(D

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