title: A heptapeptide repeat contributes to the unusual length of chloroplast ribosomal protein S18. Nucleotide sequence and map position of the rpl33-rps18 gene cluster in maize.
abstract: The rpl33-rps18 gene cluster of the maize chloroplast genome has been mapped and sequenced. The derived amino acid sequence of the S18 protein shows a 7-fold repeat of a hydrophilic heptapeptide domain, S K Q P F R K, in the N-terminal region. Such a sequence is absent in the E. coli S18 and in the chloroplast S18 of the lower plant liverwort. In tobacco and rice chloroplast S18 it is present 2 and 6 times, respectively. Thus a long N-terminal repeat (resembling in composition the large C-terminal heptapeptide repeat in the eukaryotic pol II) appears to be characteristic of monocot cereal S18.
authors.affiliation: Max-Planck-Institut für Molekulare Genetik, Abteilung Wittmann, Berlin, Dahlem, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Weglöhner
authors.forename: A R
authors.initials: AR
authors.lastname: Subramanian
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002736:Chloroplasts / Q000502:physiology*; D004275:DNA, Ribosomal / Q000235:genetics; D017343:Genes, Plant; D008969:Molecular Sequence Data; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012269:Ribosomal Proteins / Q000737:chemistry*; D013045:Species Specificity; D003313:Zea mays
chemical_list: D004275:DNA, Ribosomal; D012269:Ribosomal Proteins; C041184:ribosomal protein S18