English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Two phylloquinone molecules ( A  1 ), one being predominantly coordinated by PsaA subunit residues ( A  1A ) the other by those of PsaB ( A  1B ), act as intermediates in the two parallel electron transfer chains of Photosystem I. The oxidation kinetics of the two phyllosemiquinones by the iron-sulfur cluster F X  differ by approximately one order of magnitude, withA    1   A-being oxidized in about 200 ns andA    1   B-in about 20 ns. These differences are generally explained in terms of asymmetries in the driving force for F X  reduction on the two electron transfer chains. Site directed mutations of conserved amino acids composing the  A  1  binding site have been engineered on both reaction center subunits, and proved to affect selectively the oxidation lifetime of eitherA    1   A-, for PsaA mutants, orA    1   B-, for PsaB mutants. The mutation effects are here critically reviewed, also by novel modeling simulations employing the tunneling formalism to estimate the electron transfer rates. Three main classes of mutation effects are in particular addressed: (i) those leading to an acceleration, (ii) those leading to a moderated slowing (~5-folds), and (iii) those leading to a severe slowing (&gt;20-folds) of the kinetics. The effect of specific amino acid perturbations contributing to the poising of the phylloquinones redox potential and, in turn, to PSI functionality, is discussed.

Kinetics and Energetics of Phylloquinone Reduction in Photosystem I: Insight From Modeling of the Site Directed Mutants