Energy transfer between photosystem II units in a connected package model of the photochemical apparatus of photosynthesis

摘要

A model of the photochemical apparatus of photosynthesis, presented previously in a tripartite format, is used in a bipartite format to analyze energy transfer between photosystem II units. The model is used to develop analytical expressions for the photochemical properties of chloroplasts that include a term for the probability for energy transfer between photosystem II units. In particular, a normalized plot of the fluorescence of variable yield as a function of the closure of photosystem II reaction centers permits the evaluation of the energy transfer parameter. Data from a study by Melis [Melis, A. (1978) FEBS Lett. 95, 202-206] are used to estimate that the probability for energy transfer between photosystem II units in the α component of photosystem II was approximately 0.57 when the photosystem II reaction centers were all open and 0.83 when the centers were closed. This connected package model appears to provide a better description of the system than the matrix model that was used previously.