Chlorophyll transition dipole moment orientations and pathways for flow ofexcitation energy among the chlorophylls of the major plant antenna, LHCII

We have attempted in this work an assignment of the Q(y) dipole moment orie ntations for all the chlorophylls in the major plant antenna, light-harvest ing complex II (LHCII). Information that has recently become available thro ugh a structural model of the LHCII, site-directed mutagenesis, and spectro scopy of both LHCII and CP29 has been evaluated to model the electronic exc ited state structure in the presence of chlorophyll-chlorophyll and chlorop hyll-protein interactions. An assignment has been obtained which satisfacto rily reproduces the polarized linear absorption characteristics. The assign ment proposed has also been found to be adequate in reproducing the time sc ales of the energy transfer processes. The pathways for the flow of excitat ion energy among the chlorophylls of the complex have been suggested in the context of identity and orientation assignments.