title: An open reading frame encoding a putative haem-binding polypeptide is cotranscribed with the pea chloroplast gene for apocytochrome f.
abstract: The nucleotide sequence of a 1 kbp region of pea chloroplast DNA upstream from the gene petA encoding apocytochrome f has been determined. An open reading frame of 231 codons (ORF231) encoding a putative membrane-spanning polypeptide is separated by 205 bp from the coding region of petA. The open reading frame is homologous to open reading frames located in a similar position with respect to petA in chloroplast DNA from Marchantia polymorpha, tobacco, rice, wheat and Vicia faba. The sequence around a conserved histidine residue in a putative membrane-spanning region of the polypeptide resembles sequences present in cytochrome b from chromaffin granules and neutrophil membranes, suggesting that the open reading frame may encode a haem-binding polypeptide, possibly a b-type cytochrome. Northern hybridisation analysis indicates the presence in pea chloroplasts of a complex pattern of transcripts containing ORF231. Large transcripts of 5.5 kb, 4.3 kb, 3.4 kb and 2.7 kb encode both ORF231 and apocytochrome f, indicating that ORF231 and petA are co-transcribed.
authors.affiliation: Botany School, Cambridge Centre for Molecular Recognition, University of Cambridge, UK.
authors.forename: D L
authors.initials: DL
authors.lastname: Willey
authors.forename: J C
authors.initials: JC
authors.lastname: Gray
mesh_terms: D000595:Amino Acid Sequence; D001059:Apoproteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002736:Chloroplasts / Q000378:metabolism*; D003573:Cytochrome b Group / Q000235:genetics; D003580:Cytochromes / Q000096:biosynthesis / Q000235:genetics*; D045348:Cytochromes f; D005111:Extrachromosomal Inheritance; D007887:Fabaceae / Q000235:genetics*; D005786:Gene Expression Regulation; D017343:Genes, Plant; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010940:Plant Proteins / Q000096:biosynthesis / Q000235:genetics*; D010944:Plants / Q000235:genetics; D010946:Plants, Medicinal; D011487:Protein Conformation; D012333:RNA, Messenger / Q000096:biosynthesis; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014158:Transcription, Genetic
chemical_list: D001059:Apoproteins; D002352:Carrier Proteins; D003573:Cytochrome b Group; D003580:Cytochromes; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D008565:Membrane Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D045348:Cytochromes f