Two molecules of cytochrome c function as the electron donors to P840 in the reaction center complex isolated from a green sulfur bacterium, Chlorobium tepidum
Open Access
- 22 May 1995
- journal article
- Published by Wiley in FEBS Letters
- Vol. 365 (1) , 30-34
- https://doi.org/10.1016/0014-5793(95)00433-a
Abstract
A photoactive reaction center complex was isolated from a thermophilic green sulfur bacterium, Chlorobium tepidum under anaerobic conditions. The electron transfer occurred from heme c to the photo‐oxidized reaction center chlorophyll, P840+, with a half time () of 110 or 340 μs at 24 or 12°C, respectively. Optical measurements under multiflash excitations indicated that two hemes function as the immediate electron donors to P840+. SDS‐PAGE analysis of the RC complex in combination with the N‐terminal amino acid sequence analyses revealed five subunit bands; a core protein (65 kDa), the light harvesting bacteriochlorophyll a protein (41 kDa), a protein with 2[4Fe‐4S] clusters (31 kDa), monoheme cytochrome c (22 kDa), and a 18‐kDa protein whose function is unknown. The reaction center complex, thus, contains two molecules of cytochrome c per P840.Keywords
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