Abstract
Light-harvesting chlorophyll a/b protein II (LHCP) is encoded in the nucleus and synthesized in the cytoplasm as a precursor (pLHCP). It is imported into chloroplasts, processed to the mature form and assembled in the light-harvesting complex of PS III. Processing was reported to occur in one step in the stroma2,3. However, the precursor has been observed in thyla-koids4 and processing was reported to take place there5. A truncated precursor was transiently observed during import of pLHCP and was suggested to be an envelope-bound processing intermediate6. We have observed two truncated forms of pLHCP, intermediate in size between the precursor and mature proteins. These two forms were observed during import by intact plastids or after incubation of the precursor with plastid lysates or extracts of lumen proteins. The targeting and intra-organellar sorting of nuclear-encoded plastidial7 and mitochondrial8 proteins often occurs in several steps, e.g. lumen proteins9 and Rubisco small subunit10. It is assumed that the transit peptide can carry composite information that determines targeting to the organelle or to a particular compartment in it11,12 We examined the possibility that the two truncated forms of pLHCP observed, are intermediates in its import and processing.
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© 1992 Springer Science+Business Media New York
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Sommer, A., Ne’eman, E., Harel, E. (1992). Processing of the Light-Harvesting Chlorophyll a/b Protein II Precursor — Possible Intermediate Steps Examined by Using Truncated Precursors. In: Argyroudi-Akoyunoglou, J.H. (eds) Regulation of Chloroplast Biogenesis. Nato ASI Series, vol 226. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-3366-5_21
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DOI: https://doi.org/10.1007/978-1-4615-3366-5_21
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