ABSTRACT
When I first looked at the historic report on the X-ray
crystallographic analysis of light-harvesting complex LH2 from
Rhodopseudomonas purple bacteria, I was greatly astonished [1]. In B850, many bacteriochlorophylls are organized systematically into
a large macroring. Soon, cryomicroscopy reported the structure of
LH1 as a similarly organized ring [2]. The difference between these
two antennae was the number of bacteriochlorophylls, 18 and 32
for LH2 and LH1, respectively. Later, the LH1 structure was dis-
cussed from the viewpoint of the forbidden nature of the opti-
cal transition of a true circular structure and also the lack of an
exit site for the reduced quinone from the LH1-reaction center
composite, and another structure of an ellipse form [3] or another
having an open mouth was also reported [4, 5]. Irrespective of these
differences, the most important feature of these antenna systems
comes from the ring architecture constructed from many members
of bacteriochlorophylls in a supramolecular fashion by the conduct-
ing action of polypeptides. Later on, atomic force microscopy (AFM)
studies elucidated the closely packed assembly of the LH1-reaction
center composite and LH2 in the membrane [6-9]. Furthermore,
the control of the numbers and species of participating antennae
were found to be dependent on light intensities [10, 11]. The nat-
ural working system was so nicely designed and seemed to be far
beyond the power of synthetic organic chemists.
