FIGURE 5.

Probing incremental optimality of peripheral chlorophylls. (a) The histogram shows quantum yields within an ensemble of 4000 configurations where the chlorophylls of the Lhca1 and Lhca4 subunits are randomly reoriented. The vertical arrow denotes the quantum yield corresponding to the original geometry. It is seen that the overall quantum yield depends only minutely on the Lhca chlorophyll geometry and within that variation the original configuration shows no signs of optimality. A variation of gap chlorophyll geometries reveals a similar result regarding their effect on quantum yield (not shown). (b) The histogram shows the transfer rate from all Lhca chlorophylls to gap chlorophylls within an ensemble of 5000 configurations where the 10 gap chlorophylls are randomly reoriented. The vertical arrow denotes the transfer rate corresponding to the original geometry. It is seen that within the given model, gap chlorophyll orientations do not optimize rapid delivery from Lhca subunits even though their presence is essential for efficient coupling to the PSI core.