Possible Role of psbJ in Photosystem H: Site-Directed Mutagenesis in the Cyanobacterium, Synechocystis 6803
The unicellular transformable cyanobacterium Svnechocvstis 6803 is ideally suited for genetic analysis of the photosystem II complex in thylakoid membranes (1–3). Initially, we used a homologous probe from spinach chloroplasts to clone two neighboring genes psbE and psbF. encoding the a and the β subunits of the cytochrome b559 protein of PS II. During our examination of the organization of these two genes and the neighboring DNA regions, we have discovered the presence of two open reading frames downstream of the psbF gene. Northern analysis indicate that a ~1kb mRNA, transcribed from the entire psbEFIJ region is present in spinach (4), Euglena (5), as well as Svnechocvstis 6803 (H. Pakrasi, unpublished observation). Since cotranscribed genes usually encode proteins of the same complex, these ORF’s are thought to be related to PSII and are thus termed psbl and psbJ, respectively.
KeywordsSpinach Chloroplast Derive Amino Acid Sequence Artificial Electron Acceptor Translation Stop Codon Homologous Probe
Unable to display preview. Download preview PDF.
- 6.Eggenberger, A. and Pakrasi, H.B. (1988) Anal. Bioch., submitted for publication.Google Scholar
- 8.Cantrell, A. and Bryant, D.A. (1987) In: Progress in Photosyn. Res. IV 10: 659–662.Google Scholar
- 11.Gray, J. (May, 1988) Proceedings of the Pennsylvannia State University Symposium, In press.Google Scholar