Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2051860 | FEBS Letters | 2006 | 4 Pages |
Abstract
To elucidate the role of the non-heme iron complex (Fe-complex) in the electron transfer (ET) events of bacterial photosynthetic reaction centers (bRC), we calculated redox potentials of primary/secondary quinones QA/B (Em(QA/B)) in the Fe-depleted bRC. Removing the Fe-complex, the calculated Em(QA/B) are downshifted by ∼220 mV/∼80 mV explaining both the 15-fold decrease in ET rate from bacteriopheophytin (HA-) to QA and triplet state occurrence in Fe-depleted bRC. The larger downshift in Em(QA) relative to Em(QB) increases the driving-energy for ET from QA to QB by 140 meV, in agreement with ∼100 meV increase derived from kinetic studies.
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Authors
Hiroshi Ishikita, Ernst-Walter Knapp,