title: 5S rRNA modification in the hyperthermophilic archaea Sulfolobus solfataricus and Pyrodictium occultum.
abstract: The 5S rRNAs from Sulfolobus solfataricus and Pyrodictium occultum were digested to nucleosides and analyzed using directly-combined HPLC/mass spectrometry. P. occultum 5S rRNA contains two modified nucleoside species, N4-acetylcytidine (ac4C) and N4-acetyl-2'-O-methylcytidine (ac4Cm). Oligonucleotides were generated from P. occultum 5S rRNA by RNase T1 hydrolysis, and their molecular weights were determined using electrospray mass spectrometry and compared with those predicted from the P. occultum 5S RNA gene sequence. Deviation in mass between expected and observed molecular weights permitted ac4Cm to be located at position 35, in the nonanucleotide CAA-CACC[ac4Cm]G, and the ac4C in one or both of two (C,U)G trinucleotides. 2'-O-Methylcytidine is unambiguously characterized in S. solfataricus 5S rRNA, confirming earlier tentative assignments at the analogous sequence position (Stahl, D.A., Luehrsen, K.R., Woese, C.R., and Pace, N.R. (1981) Nucleic Acids Res., Vol. 9, pp. 6129-6137; Dams, E., Londei, P., Cammarano, P., Vandenberghe, A., and De Wachter, R. (1983) Nucleic Acids Res. Vol. 11, pp. 4667-4676). Potential effects of the presence of ac4C and ac4Cm on thermal stabilization of 5S rRNA in thermophiles are discussed.
authors.affiliation: Department of Medicinal Chemistry, University of Utah, Salt Lake City 84112.
authors.forename: E
authors.initials: E
authors.lastname: Bruenger
authors.forename: J A
authors.initials: JA
authors.lastname: Kowalak
authors.forename: Y
authors.initials: Y
authors.lastname: Kuchino
authors.forename: J A
authors.initials: JA
authors.lastname: McCloskey
authors.forename: H
authors.initials: H
authors.lastname: Mizushima
authors.forename: K O
authors.initials: KO
authors.lastname: Stetter
authors.forename: P F
authors.initials: PF
authors.lastname: Crain
mesh_terms: D001105:Archaea / Q000737:chemistry*; D001483:Base Sequence; D003562:Cytidine / Q000031:analogs & derivatives* / Q000032:analysis; D006358:Hot Temperature; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D009705:Nucleosides / Q000032:analysis*; D012341:RNA, Ribosomal, 5S / Q000737:chemistry* / Q000187:drug effects; D006163:Ribonuclease T1 / Q000494:pharmacology; D016944:Sulfolobus
chemical_list: D009705:Nucleosides; D012341:RNA, Ribosomal, 5S; D003562:Cytidine; D006163:Ribonuclease T1; C016568:5-methylcytidine