Dataset Information

Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I.

ABSTRACT: The absence of the PsaC subunit in the photosystem I (PSI) complex (native PSI complex) by mutagenesis or chemical manipulation yields a PSI core (P700-F(X) core) that also lacks subunits PsaD and PsaE and the two iron-sulfur clusters F(A) and F(B), which constitute an integral part of PsaC. In this P700-F(X) core, the redox potentials (E(m)) of the two quinones A(1A/B) and the iron-sulfur cluster F(X) as well as the corresponding protonation patterns are investigated by evaluating the electrostatic energies from the solution of the linearized Poisson-Boltzmann equation. The B-side specific Asp-B558 changes its protonation state significantly upon isolating the P700-F(X) core, being mainly protonated in the native PSI complex but ionized in the P700-F(X) core. In the P700-F(X) core, E(m)(A(1A/B)) remains practically unchanged, whereas E(m)(F(X)) is upshifted by 42 mV. With these calculated E(m) values, the electron transfer rate from A(1) to F(X) in the P700-F(X) core is estimated to be slightly faster on the A(1A) side than that of the wild type, which is consistent with kinetic measurements.

SUBMITTER: Ishikita H

PROVIDER: S-EPMC1367094 | biostudies-literature | 2006 Feb

REPOSITORIES: biostudies-literature

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Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I.

Ishikita Hiroshi H Stehlik Dietmar D Golbeck John H JH Knapp Ernst-Walter EW

Biophysical journal 20051028 3

The absence of the PsaC subunit in the photosystem I (PSI) complex (native PSI complex) by mutagenesis or chemical manipulation yields a PSI core (P700-F(X) core) that also lacks subunits PsaD and PsaE and the two iron-sulfur clusters F(A) and F(B), which constitute an integral part of PsaC. In this P700-F(X) core, the redox potentials (E(m)) of the two quinones A(1A/B) and the iron-sulfur cluster F(X) as well as the corresponding protonation patterns are investigated by evaluating the electrost ...[more]

PMID: 16258043

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Dataset Information

Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I.

Publications

Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in photosystem I.

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