title: SecA is plastid-encoded in a red alga: implications for the evolution of plastid genomes and the thylakoid protein import apparatus.
abstract: Partial sequence analysis of the plastid DNA (ptDNA) from a red alga, Antithamnion sp., revealed the presence of a homologue to the Escherichia coli secA gene as well as two open reading frames (ORF 510, ORF 179). In addition a sec Y homologue has been detected on the plastid genome by heterologous hybridization. None of these genes has been found in completely sequenced chlorophytic plastid genomes. SecA and secY gene copies were also detected in the ptDNA of a chromophytic alga, indicating that secA Y may be ubiquitous in rhodophytes and chromophytes. The significance of these findings for the evolution of plastid genomes and the thylakoid protein import mechanism is discussed.
authors.affiliation: Department of Botany, University of Washington, Seattle 98195.
authors.forename: K
authors.initials: K
authors.lastname: Valentin
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D005075:Biological Evolution; D001692:Biological Transport; D002734:Chlorophyll / Q000235:genetics; D002736:Chloroplasts / Q000502:physiology*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D056890:Eukaryota / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D016678:Genome; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics; D010788:Photosynthesis / Q000502:physiology; D000461:Rhodophyta / Q000235:genetics*; D000069816:SEC Translocation Channels; D000081416:SecA Proteins; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; D002734:Chlorophyll; C037184:chlorophyll b; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins