期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1982
卷号：79
期号：19
页码：5948-5952
DOI：10.1073/pnas.79.19.5948
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Ribosomal small subunits are organized in three general structural patterns that correspond to the eubacterial, archaebacterial, and eukaryotic lineages. Within each of these lineages, ribosomal structure is highly conserved. Small subunits from all three lineages share a common overall structure except for the following differences: (i) small subunits from archaebacteria and from the cytoplasmic component of eukaryotes both contain a feature on the head of the subunit, the archaebacterial bill, that is absent in eubacteria, and (ii) eukaryotic small subunits contain additional regions of density at the base of the subunit, the eukaryotic lobes, that are absent in archaebacteria and in eubacteria. We interpret the intralineage conservation of ribosomal three-dimensional structure as forming a phylogenetic basis for regarding archaebacteria, eubacteria, and eukaryotes as primitive lines. Although our data are separate and independent from those of Woese and Fox, they lend further support to their proposal [Woese, C. R. & Fox, G. E. (1977) Proc. Natl. Acad. Sci. USA 74, 5088-5090]. These data also provide a simple, rapid, and accurate method for classifying organisms and for identifying new lineages. Finally, interlineage variation of ribosomal structure is used to establish a rigorous framework for considering the evolution of these three lines.
