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The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins

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The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins. / Farver, O; Skov, L K; van de Kamp, M; Canters, G W; Pecht, I.

I: European Journal of Biochemistry, Bind 210, Nr. 2, 01.12.1992, s. 399-403.

Publikation: Bidrag til tidsskriftTidsskriftartikel

Harvard

Farver, O, Skov, LK, van de Kamp, M, Canters, GW & Pecht, I 1992, 'The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins', European Journal of Biochemistry, bind 210, nr. 2, s. 399-403.

APA

Farver, O., Skov, L. K., van de Kamp, M., Canters, G. W., & Pecht, I. (1992). The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins. European Journal of Biochemistry, 210(2), 399-403.

Vancouver

Farver O, Skov LK, van de Kamp M, Canters GW, Pecht I. The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins. European Journal of Biochemistry. 1992 dec 1;210(2):399-403.

Author

Farver, O ; Skov, L K ; van de Kamp, M ; Canters, G W ; Pecht, I. / The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins. I: European Journal of Biochemistry. 1992 ; Bind 210, Nr. 2. s. 399-403.

Bibtex

@article{44144bb7d79d4743ae6fe5d05f428c4e,
title = "The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins",
abstract = "An intramolecular electron-transfer process has previously been shown to take place between the Cys3--Cys26 radical-ion (RSSR-) produced pulse radiolytically and the Cu(II) ion in the blue single-copper protein, azurin [Farver, O. & Pecht, I. (1989) Proc. Natl Acad. Sci. USA 86, 6868-6972]. To further investigate the nature of this long-range electron transfer (LRET) proceeding within the protein matrix, we have now investigated it in two azurins where amino acids have been substituted by single-site mutation of the wild-type Pseudomonas aeruginosa azurin. In one mutated protein, a methionine residue (Met44) that is proximal to the copper coordination sphere has been replaced by a positively charged lysyl residue ([M44K]azurin), while in the second mutant, another residue neighbouring the Cu-coordination site (His35) has been replaced by a glutamine ([H35Q]azurin). Though both these substitutions are not in the microenvironment separating the electron donor and acceptor, they were expected to affect the LRET rate because of their effect on the redox potential of the copper site and thus on the driving force of the reaction, as well as on the reorganization energies of the copper site. The rate of intramolecular electron transfer from RSSR- to Cu(II) in the wild-type P. aeruginosa azurin (delta G degrees = -68.9 kJ/mol) has previously been determined to be 44 +/- 7 s-1 at 298 K, pH 7.0. The [M44K]azurin mutant (delta G degrees = -75.3 kJ/mol) was now found to react considerably faster (k = 134 +/- 12 s-1 at 298 K, pH 7.0) while the [H35Q]azurin mutant (delta G degrees = -65.4 kJ/mol) exhibits, within experimental error, the same specific rate (k = 52 +/- 11 s-1, 298 K, pH 7.0) as that of the wild-type azurin. From the temperature dependence of these LRET rates the following activation parameters were calculated: delta H++ = 37.9 +/- 1.3 kJ/mol and 47.2 +/- 0.7 kJ/mol and delta S++ = -86.5 +/- 5.8 J/mol.K and -46.4 +/- 4.4 J/mol.K for [H35Q]azurin and [M44K]azurin, respectively. Using the Marcus relation for intramolecular electron transfer and the above parameters we have determined the reorganization energy, lambda and electronic coupling factor, beta. The calculated values fit very well with a through-bond LRET mechanism.",
keywords = "Azurin, Copper, Cysteine, Electron Transport, Hydrogen Bonding, Hydrogen-Ion Concentration, Kinetics, Molecular Structure, Mutagenesis, Pseudomonas aeruginosa, Spectrophotometry, Thermodynamics",
author = "O Farver and Skov, {L K} and {van de Kamp}, M and Canters, {G W} and I Pecht",
year = "1992",
month = "12",
day = "1",
language = "English",
volume = "210",
pages = "399--403",
journal = "European Journal of Biochemistry",
issn = "0014-2956",
publisher = "Springer Verlag",
number = "2",

}

RIS

TY - JOUR

T1 - The effect of driving force on intramolecular electron transfer in proteins. Studies on single-site mutated azurins

AU - Farver, O

AU - Skov, L K

AU - van de Kamp, M

AU - Canters, G W

AU - Pecht, I

PY - 1992/12/1

Y1 - 1992/12/1

N2 - An intramolecular electron-transfer process has previously been shown to take place between the Cys3--Cys26 radical-ion (RSSR-) produced pulse radiolytically and the Cu(II) ion in the blue single-copper protein, azurin [Farver, O. & Pecht, I. (1989) Proc. Natl Acad. Sci. USA 86, 6868-6972]. To further investigate the nature of this long-range electron transfer (LRET) proceeding within the protein matrix, we have now investigated it in two azurins where amino acids have been substituted by single-site mutation of the wild-type Pseudomonas aeruginosa azurin. In one mutated protein, a methionine residue (Met44) that is proximal to the copper coordination sphere has been replaced by a positively charged lysyl residue ([M44K]azurin), while in the second mutant, another residue neighbouring the Cu-coordination site (His35) has been replaced by a glutamine ([H35Q]azurin). Though both these substitutions are not in the microenvironment separating the electron donor and acceptor, they were expected to affect the LRET rate because of their effect on the redox potential of the copper site and thus on the driving force of the reaction, as well as on the reorganization energies of the copper site. The rate of intramolecular electron transfer from RSSR- to Cu(II) in the wild-type P. aeruginosa azurin (delta G degrees = -68.9 kJ/mol) has previously been determined to be 44 +/- 7 s-1 at 298 K, pH 7.0. The [M44K]azurin mutant (delta G degrees = -75.3 kJ/mol) was now found to react considerably faster (k = 134 +/- 12 s-1 at 298 K, pH 7.0) while the [H35Q]azurin mutant (delta G degrees = -65.4 kJ/mol) exhibits, within experimental error, the same specific rate (k = 52 +/- 11 s-1, 298 K, pH 7.0) as that of the wild-type azurin. From the temperature dependence of these LRET rates the following activation parameters were calculated: delta H++ = 37.9 +/- 1.3 kJ/mol and 47.2 +/- 0.7 kJ/mol and delta S++ = -86.5 +/- 5.8 J/mol.K and -46.4 +/- 4.4 J/mol.K for [H35Q]azurin and [M44K]azurin, respectively. Using the Marcus relation for intramolecular electron transfer and the above parameters we have determined the reorganization energy, lambda and electronic coupling factor, beta. The calculated values fit very well with a through-bond LRET mechanism.

AB - An intramolecular electron-transfer process has previously been shown to take place between the Cys3--Cys26 radical-ion (RSSR-) produced pulse radiolytically and the Cu(II) ion in the blue single-copper protein, azurin [Farver, O. & Pecht, I. (1989) Proc. Natl Acad. Sci. USA 86, 6868-6972]. To further investigate the nature of this long-range electron transfer (LRET) proceeding within the protein matrix, we have now investigated it in two azurins where amino acids have been substituted by single-site mutation of the wild-type Pseudomonas aeruginosa azurin. In one mutated protein, a methionine residue (Met44) that is proximal to the copper coordination sphere has been replaced by a positively charged lysyl residue ([M44K]azurin), while in the second mutant, another residue neighbouring the Cu-coordination site (His35) has been replaced by a glutamine ([H35Q]azurin). Though both these substitutions are not in the microenvironment separating the electron donor and acceptor, they were expected to affect the LRET rate because of their effect on the redox potential of the copper site and thus on the driving force of the reaction, as well as on the reorganization energies of the copper site. The rate of intramolecular electron transfer from RSSR- to Cu(II) in the wild-type P. aeruginosa azurin (delta G degrees = -68.9 kJ/mol) has previously been determined to be 44 +/- 7 s-1 at 298 K, pH 7.0. The [M44K]azurin mutant (delta G degrees = -75.3 kJ/mol) was now found to react considerably faster (k = 134 +/- 12 s-1 at 298 K, pH 7.0) while the [H35Q]azurin mutant (delta G degrees = -65.4 kJ/mol) exhibits, within experimental error, the same specific rate (k = 52 +/- 11 s-1, 298 K, pH 7.0) as that of the wild-type azurin. From the temperature dependence of these LRET rates the following activation parameters were calculated: delta H++ = 37.9 +/- 1.3 kJ/mol and 47.2 +/- 0.7 kJ/mol and delta S++ = -86.5 +/- 5.8 J/mol.K and -46.4 +/- 4.4 J/mol.K for [H35Q]azurin and [M44K]azurin, respectively. Using the Marcus relation for intramolecular electron transfer and the above parameters we have determined the reorganization energy, lambda and electronic coupling factor, beta. The calculated values fit very well with a through-bond LRET mechanism.

KW - Azurin

KW - Copper

KW - Cysteine

KW - Electron Transport

KW - Hydrogen Bonding

KW - Hydrogen-Ion Concentration

KW - Kinetics

KW - Molecular Structure

KW - Mutagenesis

KW - Pseudomonas aeruginosa

KW - Spectrophotometry

KW - Thermodynamics

M3 - Journal article

C2 - 1459124

VL - 210

SP - 399

EP - 403

JO - European Journal of Biochemistry

JF - European Journal of Biochemistry

SN - 0014-2956

IS - 2

ER -

ID: 113626623