title: Chemical conversion of cytidine residues into 4-thiouridines in yeast tRNAPhe. Determination of the modified cytidines.
abstract: Treatment of yeast phenylalanine tRNA with pressurized hydrogen sulfide results in conversion of cytidine residues into 4-thiouridine residues. Under conditions leading to an average modification of one cytidine per tRNA molecule 9 positions are thiolated. The 4-thiouridine residues are distributed along the tRNA molecule. Four of the reactive cytidines are located in single-stranded regions: Cm32 , C60 , C74 and C75 . The five others are located in base pairs: C2, C27, C56 , C61 and C63 . Importance of replacement of an amino group by a thiol group on hydrogen bonding and on biological activity of the modified tRNA is discussed.
mesh_terms: D001345:Autoradiography; D001483:Base Sequence; D003562:Cytidine / Q000032:analysis*; D006868:Hydrolysis; D009690:Nucleic Acid Conformation; D010761:Phosphorus Radioisotopes; D012346:RNA, Transfer, Amino Acyl / Q000302:isolation & purification*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D013891:Thiouridine / Q000032:analysis*
chemical_list: D010761:Phosphorus Radioisotopes; D012346:RNA, Transfer, Amino Acyl; D013891:Thiouridine; D003562:Cytidine