The first determination of pseudouridine residues in 23S ribosomal RNA from hyperthermophilic Archaea Sulfolobus acidocaldarius

We describe the first identification of pseudouridine (Psi) residues in rib osomal RNA (23S rRNA) of an hyperthermophilic Archaea Sulfolobus acidocalda rius. In contrast to Eucarya rRNA, only sis Psi residues mere detected, whi ch is rather close to the situation in Bacteria, However, three modified po sitions (Psi(2479), Psi(2535) and Psi(2550)) are unique for S. acidocaldari us. Two Y residues at positions 2060 and 2594 are universally conserved, wh ile one other Psi (position 2066) is also common to Eucarya. Taken together the results argue against the conservation of Psi-synthases between Archae a and Bacteria and provide a basis for the search of snoRNA-like guides for Psi formation in Archaea. (C) 1999 Federation of European Biochemical Soci eties.