Melih Sener, Johan Strümpfer, Abhishek Singharoy, C. Neil Hunter, and Klaus
Schulten.
Overall energy conversion efficiency of a photosynthetic vesicle.
eLife, 10.7554/eLife.09541, 2016.
(30 pages).
(PMC: PMC5001839)
SENE2016
The chromatophore of purple bacteria is
an intracellular spherical vesicle that exists in numerous copies in the cell and
that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions.
Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle.
after identifying quinol turnover at
the cytochrome bc1 complex (cytbc1)
as rate limiting and
assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state.
For an illumination condition equivalent to 1% of full sunlight,
the vesicle exhibits an ATP production rate of
82 ATP
molecules/s.
The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight
is calculated to be 0.12-0.04, respectively.
The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover
for the benefit of protection against over-illumination.
Download Full Text
The manuscripts available on our site are provided for your personal
use only and may not be retransmitted or redistributed without written
permissions from the paper's publisher and author. You may not upload any
of this site's material to any public server, on-line service, network, or
bulletin board without prior written permission from the publisher and
author. You may not make copies for any commercial purpose. Reproduction
or storage of materials retrieved from this web site is subject to the
U.S. Copyright Act of 1976, Title 17 U.S.C.
