... whilst other components of the system (photo-system I an d the H+-ATPase) are located in the unstackedthylakoid membranes [1±3]. The location o f t he fourthcomponent of the photosynthetic system, ... survey of previous structural studies of thylakoid membranes [13,16,17,21, 29±32] suggests thatthey may be newly interpreted in terms of the alternative model of thylakoid structure. A review of ... reasonably evenly sampled by the data. Neverthe-less, the physical restriction imposed by the specimen holderin the microscope means that there is a Ômissing coneÕ of datacorresponding to tilts beyond...