Environmental Engineering Reference
In-Depth Information
Fig. 4
Organization of
the ET cofactors in the
RC of PSI, based on the
X-ray crystal structure of
cyanobacterial PSI [1JB0]
(Jordan et al.
2001
), and
using the nomenclature
suggested by Redding and
van der Est (Redding and
van der Est
2006
) (Figure
is generated using UCSF
Chimera).
Data source
Müller et al. (
2010
)
(analogous to the accessory bacteriochlorophylls), and two chlorophylloid. Based
on the crystal structures, it is generally assumed that the PSI core complexes, par-
ticularly the cofactor arrangement in the reaction centre, are similar in all organ-
isms and plants (Jordan et al.
2001
; Ben-Shem et al.
2003
).
On the other hand, crystal structure analysis of cyanobacterial photosystem II
(PSII) demonstrates that PSII monomer contains 20 subunits with a total molec-
ular mass of 350 kDa (Umena et al.
2011
). It is composed of 19 protein subu-
nits, 32-36 Chl molecules (35 Chls for
T. vulcanus
) (Umena et al.
2011
) including
chlorophyll
a
dimer (P
D1
P
D2
) and monomers (Chl
D1
and Chl
D2
), two pheophytins
a
(Pheo
D1
and Pheo
D2
), 11 ß-carotenes, more than 20 lipids, two plastoquinones
Q
A
and Q
B
, two haem irons, one non-haem iron, a tetranuclear manganese cluster
forming Mn
4
CaO
5
(H
2
O)
4
or Mn
4
CaO
4
(OH)(H
2
O)
4
, three or four calcium atoms
