Residual water modulates QA- -to-QB electron transfer in bacterial reaction centers embedded in trehalose amorphous matrices.

ABSTRACT: The role of protein dynamics in the electron transfer from the reduced primary quinone, Q(A)(-), to the secondary quinone, Q(B), was studied at room temperature in isolated reaction centers (RC) from the photosynthetic bacterium Rhodobacter sphaeroides by incorporating the protein in trehalose water systems of different trehalose/water ratios. The effects of dehydration on the reaction kinetics were examined by analyzing charge recombination after different regimes of RC photoexcitation (single laser pulse, double flash, and continuous light) as well as by monitoring flash-induced electrochromic effects in the near infrared spectral region. Independent approaches show that dehydration of RC-containing matrices causes reversible, inhomogeneous inhibition of Q(A)(-)-to-Q(B) electron transfer

SUBMITTER: Francia F 

PROVIDER: S-EPMC1303499 | biostudies-literature | 2003 Oct

REPOSITORIES: biostudies-literature