Molecular characterization and overexpression of the petF gene from Synechococcus elongatus: evidence for a second site of electrostatic interaction between ferredoxin and the PS I-D subunit

• Published in: Photosynthesis research Vol. 54; no. 1; pp. 63 - 71
• Main Authors: Flob, B, Igloi, G.L, Cassier-Chauvat, C, Muhlenhoff, U
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.10.1997
• Subjects: amino acid sequences; binding sites; Cyanobacteria; E coli; Escherichia coli; ferredoxin; genbank /y10288; gene expression; genes; molecular sequence data; NADP (coenzyme); nucleotide sequences; photosystem I; proteins; redox reactions; site-directed mutagenesis; Synechococcus; Synechococcus elongatus; Synechocystis
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1023/A:1005823620291

The petF gene from the cyanobacterium Synechococcus elongatus was isolated using the same gene from Synechocystis sp. PCC 6803 as a heterologous probe. The deduced primary sequence of the isolated single copy petF gene is identical to the primary sequence determined from the protein. Wild-type ferredoxin and a E93-95/Q93-95 mutant were overexpressed in E. coli and purified. Both types of ferredoxins are photoreduced by Photosystem I and can be cross-linked to the PsaD subunit of PS I, although with reduced affinity in case of the E93-95/Q93-95 mutant. These data indicate that the acidic patch of amino acids Glu94-95 of ferredoxin is most likely neither essential for the interaction of ferredoxin with PS I nor the only site of electrostatic contact with the PS I-D subunit. In contrast, NADP^sup +^photoreduction assays show drastically reduced rates in the presence of the E93-95/Q93-95 mutant ferredoxin, indicating that these residues play a crucial role in the interaction of ferredoxin with ferredoxin-NADP^sup +^reductase.[PUBLICATION ABSTRACT]