High-resolution
AFM images showing example arrangements of LH2s
and core complexes. (a) Hexagonal packing of LH2 rings (green *).
Also in (a), there are three rows of LH2 rings between two core complexes
(red ×). (b) LH2-rich region where there are some “empty
lipid” regions (yellow dots). “Empty lipid” regions
1 and 2 are surrounded by five LH2 rings, while “empty lipid”
region 3 is surrounded by six LH2 rings. LH2 ring 1 is surrounded
by seven LH2 rings, LH2 rings 2, 3, and 4 are surrounded by five rings
and an “empty lipid” region, while LH2 ring 5 is surrounded
by four rings and two “empty lipid” regions. (c and
d) Two monomer core complexes (red dotted circle) surrounded by LH2
rings. In (c) the core is surrounded by seven LH2 rings and “empty
lipid” regions, while in (d) the core is surrounded by eight
LH2 rings. (e and f) Two core complex dimers. In (e) the dimer is
surrounded by LH2 rings and “empty lipid” regions, and
by symmetry it can be said that 10 LH2 rings and “empty lipid”
regions surround a core dimer. Also, (e) shows that each core of an
S-dimer can be in contact with up to six LH2 rings. In (f) the dimer
is surrounded by LH2 rings, “empty lipid” regions, and
another core dimer. (g) Linear arrangement of five core complexes,
and each core is in contact with at least four LH2 rings. (h) Alternate
rows of core dimers and LH2 rings. (i) Seven core complexes in two
rows next to each other with each core complex in contact with at
least two LH2 rings. Some core complexes have a lower protrusion in
the center, suggesting decapitation of parts of the RC complex, possibly
due to the imaging force.