Structure and targeted mutagenesis of the gene encoding 8-kDa subunit of photosystem I from the cyanobacterium Synechocystis sp. PCC 6803.
Photosystem I reaction center of the cyanobacterium Synechocystis sp. PCC 6803 contains seven different polypeptide subunits. The subunit with a molecular mass of about 8 kDa was isolated, and the sequence of its amino-terminal residues was determined. Oligonucleotide probes corresponding to this sequence were used to isolate the gene encoding this subunit. The gene, termed as psaE, codes for a polypeptide with a mass of 8075 Da. It is present as a single copy in the genome and is transcribed as a monocistronic messenger. The amino acid sequence of the 8-kDa subunit deduced from the gene sequence shows high homology with the deduced amino acid sequence of subunit IV of photosystem I from spinach. The DNA fragment sequenced in these studies also contains two other unidentified major open reading frames. A stable deletion mutation for the psaE gene was generated by transforming Synechocystis sp. PCC 6803 with a cloned DNA in which the psaE gene for 8-kDa subunit was replaced by a gene conferring resistance to kanamycin. The mutant strain shows minor differences in growth under photoautotrophic conditions and in the photosystem I activity in comparison to the wild type.
Chitnis
P R
PR
Roche Institute of Molecular Biology, Roche Research Center, Nutley, New Jersey.
Reilly
P A
PA
Miedel
M C
MC
Nelson
N
N
D000595:Amino Acid Sequence; D001483:Base Sequence; D002734:Chlorophyll / Q000235:genetics* / Q000302:isolation & purification; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000032:analysis* / Q000235:genetics / Q000254:growth & development; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009154:Mutation; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes; D010788:Photosynthesis; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins / Q000235:genetics* / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D045342:Light-Harvesting Protein Complexes; D015345:Oligonucleotide Probes; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll