Original Article

A Small Chloroplast-encoded Protein as a Novel Architectural Component of the Light-harvesting Antenna

Correspondence to: Ralph Bock, Institut für Biologie III, Universität Freiburg, Schänzlestraße 1, D-79104 Freiburg, Germany. Tel:+49-761-2032721 Fax:+49-761-2032745 E-mail:bock{at}biologie.uni-freiburg.de.

A small conserved open reading frame in the plastid genome, ycf9, encodes a putative membrane protein of 62 amino acids. To determine the function of this reading frame we have constructed a knockout allele for targeted disruption of ycf9. This allele was introduced into the tobacco plastid genome by biolistic transformation to replace the wild-type ycf9 allele. Homoplasmic ycf9 knockout plants displayed no phenotype under normal growth conditions. However, under low light conditions, their growth rate was significantly reduced as compared with the wild-type, due to a lowered efficiency of the light reaction of photosynthesis. We show that this phenotype is caused by the deficiency in a pigment–protein complex of the light-harvesting antenna of photosystem II and hence by a reduced efficiency of photon capture when light availability is limiting. Our results indicate that, in contrast to the current view, light-harvesting complexes do not only consist of the classical pigment-binding proteins, but may contain small structural subunits in addition. These subunits appear to be crucial architectural factors for the assembly and/or maintenance of stable light-harvesting complexes.

Key Words: chloroplast, LHCII, light-harvesting complex, photosynthesis, ycf9

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Bohne, A.-V., Ruf, S., Borner, T., Bock, R. (2007). Faithful transcription initiation from a mitochondrial promoter in transgenic plastids. Nucleic Acids Res 35: 7256-7266 [Abstract] [Full Text]  
• Ruf, S., Karcher, D., Bock, R. (2007). From the Cover: Determining the transgene containment level provided by chloroplast transformation. Proc. Natl. Acad. Sci. USA 104: 6998-7002 [Abstract] [Full Text]  
• Nield, J., Redding, K., Hippler, M. (2004). Remodeling of Light-Harvesting Protein Complexes in Chlamydomonas in Response to Environmental Changes. Eukaryot Cell 3: 1370-1380 [Full Text]  
• Hager, M., Hermann, M., Biehler, K., Krieger-Liszkay, A., Bock, R. (2002). Lack of the Small Plastid-encoded PsbJ Polypeptide Results in a Defective Water-splitting Apparatus of Photosystem II, Reduced Photosystem I Levels, and Hypersensitivity to Light. J. Biol. Chem. 277: 14031-14039 [Abstract] [Full Text]  
• Sheveleva, E. V., Giordani, N. V., Hallick, R. B. (2002). Identification and comparative analysis of the chloroplast {alpha}-subunit gene of DNA-dependent RNA polymerase from seven Euglena species. Nucleic Acids Res 30: 1247-1254 [Abstract] [Full Text]  
• Eckardt, N. A. (2001). A Role for PsbZ in the Core Complex of Photosystem II. Plant Cell 13: 1245-1248 [Full Text]  
• Swiatek, M., Kuras, R., Sokolenko, A., Higgs, D., Olive, J., Cinque, G., Muller, B., Eichacker, L. A., Stern, D. B., Bassi, R., Herrmann, R. G., Wollman, F.-A. (2001). The Chloroplast Gene ycf9 Encodes a Photosystem II (PSII) Core Subunit, PsbZ, That Participates in PSII Supramolecular Architecture. Plant Cell 13: 1347-1368 [Abstract] [Full Text]  
• Andersson, J., Walters, R. G., Horton, P., Jansson, S. (2001). Antisense Inhibition of the Photosynthetic Antenna Proteins CP29 and CP26: Implications for the Mechanism of Protective Energy Dissipation. Plant Cell 13: 1193-1204 [Abstract] [Full Text]  
• Baena-Gonzalez, E., Gray, J. C., Tyystjarvi, E., Aro, E.-M., Maenpaa, P. (2001). Abnormal Regulation of Photosynthetic Electron Transport in a Chloroplast ycf9 Inactivation Mutant. J. Biol. Chem. 276: 20795-20802 [Abstract] [Full Text]  

Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents