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Title: EVIDENCE FOR AN ALTERNATE ELECTRON CARRIER BETWEEN THE CYTOCHROME B6/F COMPLEX AND PS I IN SYNECHOCYSTIS 6803: IS IT CYTOCHROME M?

Author
item METZGER, S - UNIV OF ILLINOIS, URBANA
item PAKRASI, H - WASHINGTON UNIV ST. LOUIS
item WHITMARSH, CLIFFORD

Submitted to: Photosynthesis International Congress Symposium Proceedings and Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Mutant strains of Synechocystis 6803 lacking either plastocyanin (PC) or cytochrome c6 (cyt c6) can be grown so that both carriers, PC and cyt c6, are absent. The cells grow photoautotrophically and sustain normal rates of oxygen evolution and dark respiration suggesting the presence of an alternate carrier (Zhang et al., 1994, JBC, Vol. 269, pp. 5036-5042). The oxidation kinetics of cytochrome f and the reduction kinetics of P700 have been measured spectroscopically revealing that electron transfer occurs at a 4-6 times slower rate in these mutant cells than in wild-type. We created a double mutant that lacks cyt c6 and the recently discovered cytochrome M (Malakhov et al., 1994, J. Plant Physiol., Vol. 144, pp. 259-264) to investigate the possibility that the latter could act as an electron carrier between the cytochrome b/f complex and Photosystem I.