Recruitment of a foreign quinone into the A1 site of photosystem I. II. Structural and functional characterization of phylloquinone biosynthetic pathway mutants by electron paramagnetic resonance and electron-nuclear double resonance spectroscopy

Boris Zybailov, Art Van Der Est, Stephan G. Zech, Christian Teutloff, T. Wade Johnson, Gaozhong Shen, Robert Bittl, Dietmar Stehlik, Parag R. Chitnis, John H. Golbeck

Research output: Contribution to journalArticle

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Abstract

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance studies of the photosystem (PS) I quinone acceptor, A1, in phylloquinone biosynthetic pathway mutants are described. Room temperature continuous wave EPR measurements at X-band of whole cells of menA and menB interruption mutants show a transient reduction and oxidation of an organic radical with a g-value and anisotropy characteristic of a quinone. In PS I complexes, the continuous wave EPR spectrum of the photoaccumulated Q- radical, measured at Q-band, and the electron spin-polarized transient EPR spectra of the radical pair P700+ Q-, measured at X-, Q-, and W-bands, show three prominent features: (i) Q- has a larger g-anisotropy than native phylloquinone, (ii) Q- does not display the prominent methyl hyperfine couplings attributed to the 2-methyl group of phylloquinone, and (iii) the orientation of Q- in the A1 site as derived from the spin polarization is that of native phylloquinone in the wild type. Electron spin echo modulation experiments on P700+ Q- show that the dipolar coupling in the radical pair is the same as in native PS I, i.e. the distance between P700+ and Q-(25.3 ± 0.3 Å) is the same as between P700+ and A1 - in the wild type. Pulsed electron-nuclear double resonance studies show two sets of resolved spectral features with nearly axially symmetric hyperfine couplings. They are tentatively assigned to the two methyl groups of the recruited plastoquinone- 9, and their difference indicates a strong inequivalence among the two groups when in the A1 site. These results show that Q (i) functions in accepting an electron from A0 - and in passing the electron forward to the iron-sulfur clusters, (ii) occupies the A1 site with an orientation similar to that of phylloquinone in the wild type, and (iii) has spectroscopic properties consistent with its identity as plastoquinone-9.

Original languageEnglish (US)
Pages (from-to)8531-8539
Number of pages9
JournalJournal of Biological Chemistry
Volume275
Issue number12
DOIs
StatePublished - Mar 24 2000

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Vitamin K 1
Photosystem I Protein Complex
Photosystem II Protein Complex
Biosynthetic Pathways
Electron Spin Resonance Spectroscopy
Paramagnetic resonance
Spectrum Analysis
Spectroscopy
Electrons
Plastoquinone
Anisotropy
Spin polarization
Sulfur
benzoquinone
Iron
Modulation
Oxidation
Temperature

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

@article{155bd17755514e84b4e5beaa952e31f4,
title = "Recruitment of a foreign quinone into the A1 site of photosystem I. II. Structural and functional characterization of phylloquinone biosynthetic pathway mutants by electron paramagnetic resonance and electron-nuclear double resonance spectroscopy",
abstract = "Electron paramagnetic resonance (EPR) and electron-nuclear double resonance studies of the photosystem (PS) I quinone acceptor, A1, in phylloquinone biosynthetic pathway mutants are described. Room temperature continuous wave EPR measurements at X-band of whole cells of menA and menB interruption mutants show a transient reduction and oxidation of an organic radical with a g-value and anisotropy characteristic of a quinone. In PS I complexes, the continuous wave EPR spectrum of the photoaccumulated Q- radical, measured at Q-band, and the electron spin-polarized transient EPR spectra of the radical pair P700+ Q-, measured at X-, Q-, and W-bands, show three prominent features: (i) Q- has a larger g-anisotropy than native phylloquinone, (ii) Q- does not display the prominent methyl hyperfine couplings attributed to the 2-methyl group of phylloquinone, and (iii) the orientation of Q- in the A1 site as derived from the spin polarization is that of native phylloquinone in the wild type. Electron spin echo modulation experiments on P700+ Q- show that the dipolar coupling in the radical pair is the same as in native PS I, i.e. the distance between P700+ and Q-(25.3 ± 0.3 {\AA}) is the same as between P700+ and A1 - in the wild type. Pulsed electron-nuclear double resonance studies show two sets of resolved spectral features with nearly axially symmetric hyperfine couplings. They are tentatively assigned to the two methyl groups of the recruited plastoquinone- 9, and their difference indicates a strong inequivalence among the two groups when in the A1 site. These results show that Q (i) functions in accepting an electron from A0 - and in passing the electron forward to the iron-sulfur clusters, (ii) occupies the A1 site with an orientation similar to that of phylloquinone in the wild type, and (iii) has spectroscopic properties consistent with its identity as plastoquinone-9.",
author = "Boris Zybailov and {Van Der Est}, Art and Zech, {Stephan G.} and Christian Teutloff and Johnson, {T. Wade} and Gaozhong Shen and Robert Bittl and Dietmar Stehlik and Chitnis, {Parag R.} and Golbeck, {John H.}",
year = "2000",
month = "3",
day = "24",
doi = "10.1074/jbc.275.12.8531",
language = "English (US)",
volume = "275",
pages = "8531--8539",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
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}

Recruitment of a foreign quinone into the A1 site of photosystem I. II. Structural and functional characterization of phylloquinone biosynthetic pathway mutants by electron paramagnetic resonance and electron-nuclear double resonance spectroscopy. / Zybailov, Boris; Van Der Est, Art; Zech, Stephan G.; Teutloff, Christian; Johnson, T. Wade; Shen, Gaozhong; Bittl, Robert; Stehlik, Dietmar; Chitnis, Parag R.; Golbeck, John H.

In: Journal of Biological Chemistry, Vol. 275, No. 12, 24.03.2000, p. 8531-8539.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Recruitment of a foreign quinone into the A1 site of photosystem I. II. Structural and functional characterization of phylloquinone biosynthetic pathway mutants by electron paramagnetic resonance and electron-nuclear double resonance spectroscopy

AU - Zybailov, Boris

AU - Van Der Est, Art

AU - Zech, Stephan G.

AU - Teutloff, Christian

AU - Johnson, T. Wade

AU - Shen, Gaozhong

AU - Bittl, Robert

AU - Stehlik, Dietmar

AU - Chitnis, Parag R.

AU - Golbeck, John H.

PY - 2000/3/24

Y1 - 2000/3/24

N2 - Electron paramagnetic resonance (EPR) and electron-nuclear double resonance studies of the photosystem (PS) I quinone acceptor, A1, in phylloquinone biosynthetic pathway mutants are described. Room temperature continuous wave EPR measurements at X-band of whole cells of menA and menB interruption mutants show a transient reduction and oxidation of an organic radical with a g-value and anisotropy characteristic of a quinone. In PS I complexes, the continuous wave EPR spectrum of the photoaccumulated Q- radical, measured at Q-band, and the electron spin-polarized transient EPR spectra of the radical pair P700+ Q-, measured at X-, Q-, and W-bands, show three prominent features: (i) Q- has a larger g-anisotropy than native phylloquinone, (ii) Q- does not display the prominent methyl hyperfine couplings attributed to the 2-methyl group of phylloquinone, and (iii) the orientation of Q- in the A1 site as derived from the spin polarization is that of native phylloquinone in the wild type. Electron spin echo modulation experiments on P700+ Q- show that the dipolar coupling in the radical pair is the same as in native PS I, i.e. the distance between P700+ and Q-(25.3 ± 0.3 Å) is the same as between P700+ and A1 - in the wild type. Pulsed electron-nuclear double resonance studies show two sets of resolved spectral features with nearly axially symmetric hyperfine couplings. They are tentatively assigned to the two methyl groups of the recruited plastoquinone- 9, and their difference indicates a strong inequivalence among the two groups when in the A1 site. These results show that Q (i) functions in accepting an electron from A0 - and in passing the electron forward to the iron-sulfur clusters, (ii) occupies the A1 site with an orientation similar to that of phylloquinone in the wild type, and (iii) has spectroscopic properties consistent with its identity as plastoquinone-9.

AB - Electron paramagnetic resonance (EPR) and electron-nuclear double resonance studies of the photosystem (PS) I quinone acceptor, A1, in phylloquinone biosynthetic pathway mutants are described. Room temperature continuous wave EPR measurements at X-band of whole cells of menA and menB interruption mutants show a transient reduction and oxidation of an organic radical with a g-value and anisotropy characteristic of a quinone. In PS I complexes, the continuous wave EPR spectrum of the photoaccumulated Q- radical, measured at Q-band, and the electron spin-polarized transient EPR spectra of the radical pair P700+ Q-, measured at X-, Q-, and W-bands, show three prominent features: (i) Q- has a larger g-anisotropy than native phylloquinone, (ii) Q- does not display the prominent methyl hyperfine couplings attributed to the 2-methyl group of phylloquinone, and (iii) the orientation of Q- in the A1 site as derived from the spin polarization is that of native phylloquinone in the wild type. Electron spin echo modulation experiments on P700+ Q- show that the dipolar coupling in the radical pair is the same as in native PS I, i.e. the distance between P700+ and Q-(25.3 ± 0.3 Å) is the same as between P700+ and A1 - in the wild type. Pulsed electron-nuclear double resonance studies show two sets of resolved spectral features with nearly axially symmetric hyperfine couplings. They are tentatively assigned to the two methyl groups of the recruited plastoquinone- 9, and their difference indicates a strong inequivalence among the two groups when in the A1 site. These results show that Q (i) functions in accepting an electron from A0 - and in passing the electron forward to the iron-sulfur clusters, (ii) occupies the A1 site with an orientation similar to that of phylloquinone in the wild type, and (iii) has spectroscopic properties consistent with its identity as plastoquinone-9.

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