Energy transfer dynamics of the B800—B850 antenna complex of Rhodobacter sphaeroides: a hole burning study

✍ Scribed by N.R.S. Reddy; G.J. Small; M. Seibert; R. Picorel

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 872 KB
• Volume: 181
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)90369-k

✦ Synopsis

Hole burned spectra for the B800-B850 bacteriochlorophyll P anlenna complex of Rb. sphaeroides chromatophores have been obtained for burn wavelengths ranging from the high-energy side of the B800 absorption profile to the low-energy side of B850 profile. The results indicate that B800-B800 energy transfer at I .6 K is slow relative to 8800 to 8850 transfer which occurs in 2.4 ps. Whereas BXOD is largely site inhomogeneously broadened, B850 is found to exhibit a homogeneous linewidth of about 220 cm-' at low temperatures. The latter result is used to explain the temperature independence of the B800 to 8850 energy transfer rate. The homogeneous linewldth of 220 cm-' is argued to be a measure of the exciton bandwidth of B850. It is concluded that 8800 and B850 are weakly exciton-coupled and that the mechanism for BSOO to B850 energy transfer is most likely of the Farstertype. The B850 vibronic hole structure allows for an identification of bacteriochlorophyll a modes that participate in Fiirster transfer.