title: The structure and evolution of the ribosomal proteins encoded in the spc operon of the archaeon (Crenarchaeota) Sulfolobus acidocaldarius.
abstract: The genes for nine ribosomal proteins, L24, L5, S14, S8, L6, L18, S5, L30, and L15, have been isolated and sequenced from the spc operon in the archaeon (Crenarchaeota) Sulfolobus acidocaldarius, and the putative amino acid sequence of the proteins coded by these genes has been determined. In addition, three other genes in the spc operon, coding for ribosomal proteins S4E, L32E, and L19E (equivalent to rat ribosomal proteins S4, L32, and L19), were sequenced and the structure of the putative proteins was determined. The order of the ribosomal protein genes in the spc operon of the Crenarchaeota kingdom of Archaea is identical to that present in the Euryarchaeota kingdom of Archaea and also identical to that found in bacteria, except for the genes for r-proteins S4E, L32E, and L19E, which are absent in bacteria. Although AUG is the initiation codon in most of the spc genes, GUG (val) and UUG (leu) are also used as initiation codons in S. acidocaldarius. Over 70% of the codons in the Sulfolobus spc operon have A or U in the third position, reflecting the low GC content of Sulfolobus DNA. Phylogenetic analysis indicated that the archaeal r-proteins are a sister group of their eucaryotic counterparts but did not resolve the question of whether the Archaea is monophyletic, as suggested by the L6P, L15P, and L18P trees, or the question of whether the Crenarchaeota is separate from the Euryarchaeota and closer to the Eucarya, as suggested by the S8P, S5P, and L24P trees. In the case of the three Sulfolobus r-proteins that do not have a counterpart in the bacterial ribosome (S4E, L32E, and L19E), the archaeal r-proteins showed substantial identity to their eucaryotic equivalents, but in all cases the archaeal proteins formed a separate group from the eucaryotic proteins.
authors.affiliation: Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, V8W 3P6, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Yang
authors.forename: I
authors.initials: I
authors.lastname: Kusser
authors.forename: A K
authors.initials: AK
authors.lastname: Köpke
authors.forename: B F
authors.initials: BF
authors.lastname: Koop
authors.forename: A T
authors.initials: AT
authors.lastname: Matheson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019843:Archaeal Proteins / Q000737:chemistry / Q000235:genetics; D001482:Base Composition; D003001:Cloning, Molecular; D003062:Codon / Q000235:genetics; D005057:Eukaryotic Cells; D019143:Evolution, Molecular; D019766:Genes, Archaeal / Q000235:genetics*; D005798:Genes, Bacterial / Q000235:genetics; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics*; D010802:Phylogeny; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics*; D017422:Sequence Analysis, DNA; D016944:Sulfolobus / Q000145:classification / Q000235:genetics*
chemical_list: D019843:Archaeal Proteins; D003062:Codon; D012269:Ribosomal Proteins