期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1993
卷号：90
期号：5
页码：1834-1838
DOI：10.1073/pnas.90.5.1834
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Flash-induced oxygen evolution in the thylakoids of plants and algae exhibits damped oscillations with period four. These are well described by the S-state model of Kok et al. [Kok, B., Forbush, B. & McGloin, M. (1970) Photochem. Photobiol. 11, 457-475], with damping provided by empirical misses and double hits in the reaction center of photosystem II. Here we apply a mechanistic interpretation of misses as mainly determined by reaction centers that are inactive at the time of the flash due to the presence of either P+ or QA, according to the electron transfer equilibria on the donor and acceptor sides of the reaction center. Calculation of misses on this basis, using known or estimated values of the equilibrium constants for electron transfer between the S states and tyrosine Yz, between Yz and P680, as well as between the acceptor plastoquinones, allows a natural description of the flash number dependence of oxygen evolution. The calculated misses are different for each flash-induced reaction center transition. Identification of this mechanism underlying the miss factor for each transition leads to the recognition of two different reaction sequence cycles of photosystem II, with different transition probabilities, producing an intrinsic heterogeneity of photosystem II activity.
