REVIEW: Photoactive Pigment-Enzyme Complexes of Chlorophyll Precursor in Plant Leaves

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O. B. Belyaeva^* and F. F. Litvin

Faculty of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia; E-mail: olgabelyaeva@mail.ru

^* To whom correspondence should be addressed.

Received November 22, 2006

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This review summarizes contemporary data on structure and function of photoactive pigment-enzyme complexes of the chlorophyll precursor that undergoes photochemical transformation to chlorophyllide. The properties and functions of the complex and its principal components are considered including the pigment (protochlorophyllide), the hydrogen donor (NADPH), and the photoenzyme protochlorophyllide oxidoreductase (POR) that catalyzes the photochemical production of chlorophyllide. Chemical variants of the chlorophyll precursor are described (protochlorophyllide, protochlorophyll, and their mono- and divinyl forms). The nature and photochemical activity of spectrally distinct native protochlorophyllide forms are discussed. Data are presented on structural organization of the photoenzyme POR, its substrate specificity, localization in etioplasts, and heterogeneity. The significance of different POR forms (PORA, PORB, and PORC) in adaptation of chlorophyll biosynthesis to various illumination conditions is considered. Attention is paid to structural and functional interactions of three main constituents of the photoactive complex and to possible existence of additional components associated with the pigment-enzyme complex. Historical aspects of the problem and the prospects of further investigations are outlined.

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KEY WORDS: chlorophyll biosynthesis, photoreduction of protochlorophyllide, protochlorophyllide oxidoreductase, pigment-protein complexes

DOI: 10.1134/S0006297907130044

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