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. 1978 Aug;23(2):207–217. doi: 10.1016/S0006-3495(78)85443-5

Picosecond dynamics of primary electron-transfer processes in bacterial photosynthesis.

K Peters, P Avouris, P M Rentzepis
PMCID: PMC1473520  PMID: 308379

Abstract

The primary electron transfer processes in Rhodopseudomonas sphaeroides R-26 were studied as a function of temperature by means of picosecond spectroscopy. The first chemical step of the bacterial photosynthesis involves an electron transfer from the excited state of a bacteriochlorophyll a dimer, (BChl)2, to a bacteriopheophytin (BPh) to form the radical ion pair (BChl)2+. BPh-.. The upper limit for the formation time of this ion-pair was found to be 10 ps, at temperatures in the range 300-4.2 degree K. Similarly, the second chemical step, involving electron transfer from BPh-. to an ubiquinone-iron complex (QFe), was found to have a lifetime of approximately 150 ps, also independent of temperature in the same range. We interpret the absence of temperature dependence as indicating that process 2 proceeds via a tunneling mechanism. Utilizing our results in conjunction with electron tunneling theories, we calculate the distance between BPh-. and Q(Fe) to be 9--13 A. Our results also imply a closer proximity between (BChl)2 and BPh.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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