Part 4

The flanking regions on either side of the core dimer contain the LHCII, CP29, CP26 and perhaps PsbS. A high resolution structure of the LHCII trimer is known (16) and has previously been positioned towards the outer tips of the flanking region (7,12). This positioning is shown in Fig. 4, which also assumes that CP26 and CP29 have structures similar to those of a monomer of LHCII and are positioned as shown. It should be emphasised that precise positioning of these outer light harvesting proteins is speculative and may exclude other proteins such as PsbS. We have investigated the spatial relationship between the extrinsic OEC proteins and the underlying intrinsic proteins of the core dimer complex by removing the extrinsic proteins from the map at the level defined by the outer surface of slice (d) in Fig. 2b and thus provide 'windows' through which the underlying helices can be identified (e.g. Fig. 4c).