Journal of Experimental Botany, Vol. 52, No. 354, pp. 47-56,
January 2001
© 2001 Oxford University Press
Original Papers |
Chloroplast precursor proteins compete to form early import intermediates in isolated pea chloroplasts
Department of Plant Sciences and Cambridge Centre for Molecular Recognition, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK
In order to ascertain whether there is one site for the import of precursor proteins into chloroplasts or whether different precursor proteins are imported via different import machineries, chloroplasts were incubated with large quantities of the precursor of the 33 kDa subunit of the oxygen-evolving complex (pOE33) or the precursor of the light-harvesting chlorophyll a/b-binding protein (pLHCP) and tested for their ability to import a wide range of other chloroplast precursor proteins. Both pOE33 and pLHCP competed for import into chloroplasts with precursors of the stromally-targeted small subunit of Rubisco (pSSu), ferredoxin NADP+ reductase (pFNR) and porphobilinogen deaminase; the thylakoid membrane proteins LHCP and the Rieske iron-sulphur protein (pRieske protein); ferrochelatase and the
subunit of the ATP synthase (which are both associated with the thylakoid membrane); the thylakoid lumenal protein plastocyanin and the phosphate translocator, an integral membrane protein of the inner envelope. The concentrations of pOE33 or pLHCP required to cause half-maximal inhibition of import ranged between 0.2 and 4.9 µM. These results indicate that all of these proteins are imported into the chloroplast by a common import machinery. Incubation of chloroplasts with pOE33 inhibited the formation of early import intermediates of pSSu, pFNR and pRieske protein.
Key words: Chloroplast protein import, LHCP, phosphate translocator, precursor protein, Rieske protein, Rubisco, translocation.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
T. Inaba, M. Alvarez-Huerta, M. Li, J. Bauer, C. Ewers, F. Kessler, and D. J. Schnell Arabidopsis Tic110 Is Essential for the Assembly and Function of the Protein Import Machinery of Plastids PLANT CELL, May 1, 2005; 17(5): 1482 - 1496. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Ivanova, M. D. Smith, K. Chen, and D. J. Schnell Members of the Toc159 Import Receptor Family Represent Distinct Pathways for Protein Targeting to Plastids Mol. Biol. Cell, July 1, 2004; 15(7): 3379 - 3392. [Abstract] [Full Text] [PDF] |
||||

