Purification and Properties of a Thylakoidal Enzyme of Spinach Involved in the Processing of D1 Protein of PS II Reaction Center
It is generally believed that D1 and D2 proteins constitute the RC of PSII in a similar manner to the L and M subunit s forming the purple bacterial RC (1–3). On the other hand, the D1 protein is also recognized as one of the most unstable proteins in thylakoid membranes in the light and is known to be recovering rapidly through a light-regulated de novo synthesis (4). The protein is synthesized as a precursor 1–2 kDa greater in size than that of the mature form. The maturation process of the newly synthesized precursor protein is predicted to occur through a C-terminal cleavage at Ala-344 of the amino acid sequence deduced from spinach psbA gene (5,6). The processing seems to be essential for the assembly of the catalytic center for water cleavage, but not for the primary photochemistry of PSII (7,8). The enzyme has recently been solubilized from wild-type strain of Scenedesmus obliquus (8).
KeywordsSpinach Chloroplast Scenedesmus Obliquus Primary Photochemistry Unstable Protein Spinach Thylakoid
Unable to display preview. Download preview PDF.
- 2.Trebst, A. (1986) Z. Naturforsch 41C, 240–245Google Scholar
- 3.Michel, H. and Deisenhofer, J. (1986) In Encyclopedia of Plant Physiology: Photosynthesis (Staehelin L. A. and Arntzen, C. J. eds) vol.19 (new series), 371–381, Spriger, BerlinGoogle Scholar
- 6.Takahashi, Y., Nakane, H. and Satoh, K. (1989) submittedGoogle Scholar
- 8.Taylor, M. A., Packer, J. C. L. and Bowyer, J. R. (1988) FEBS Lett.Google Scholar
- 10.Fujita, S., Inagaki, N., Ono, T., Inoue, Y. and Satoh, K. (1989) FEBS Lett. In pressGoogle Scholar