Co-Authors:
Lers, A., Department of Zoology, Duke University, Durham, NC 27706, United States
Heifetz, P.B., Department of Botany, Duke University, Durham, NC 27706, United States
Boynton, J.E., Department of Botany, Duke University, Durham, NC 27706, United States
Gillham, N.W., Department of Zoology, Duke University, Durham, NC 27706, United States
Osmond, C.B., Department of Botany, Duke University, Durham, NC 27706, United States, Res. School of Biological Sciences, Australian National University, Canberra, ACT 2601, Australia
Abstract:
Synthesis of the photosystem II D1 protein as a precursor with a carboxyl-terminal extension occurs in almost all eukaryotic photosynthetic organisms examined so far, as well as in cyanobacteria. Processing of the D1 precursor has been recently postulated to play a regulatory role in the light-dependent migration of photosystem II units from the unstacked to the stacked thylakoids (Bowyer, J. M., Packer, J. C. L., McCormack, B. A., Whitelegge, J. P., Robinson, C., and Taylor, M. A. (1992) J. Biol. Chem. 267, 5424-5433). To test this hypothesis, site-directed mutagenesis and chloroplast transformation have been used to create a "preprocessed" mutant Chlamydomonas strain which synthesizes mature D1 protein directly. We have found that this strain is indistinguishable from wild type in terms of photosynthetic performance and cell doubling time under CO2- and light-saturated photoautotrophic growth conditions.