title: [Primary structure of tRNA Thr 1a and b from brewer's yeast].
abstract: One of the two major species of brewer's yeast tRNA threonine (tRNA Thr 1) has been purified by countercurrent distribution followed by two chromatographic steps (respectively on a Sepharose 4B and a BD-cellulose column). Complete digestion with pancreatic and T1 RNases and a partial hydrolysis with T1 RNase followed by the isolation and determination of the nucleotide sequences of the resulting fragments permitted the derivation of its primary structure. tRNA Thr 1 is in fact a mixture of two subspecies differing only by a A49-U65 base pair in 50 per cent of the molecules which is replaced by a G49-C65 pair in the other 50 per cent. These two subspecies consist of 76 nucleotide residues including 14 minor nucleotides. They show a characteristic m3C at the 3'terminal end of the anticodon loop, an anticodon I-G-U followed by t6A and C48, uncompletely modified (50 per cent) to m5C within the 5 nucleotides long extra-arm. The minor nucleotides m2G m2 2G are located at positions in which they generally occur in the tRNA structures as does m1A within the T-psi-C loop.
mesh_terms: D001483:Base Sequence; D003377:Countercurrent Distribution; D009843:Oligoribonucleotides / Q000032:analysis; D012343:RNA, Transfer / Q000302:isolation & purification; D006163:Ribonuclease T1; D012265:Ribonucleotides / Q000032:analysis; D012441:Saccharomyces cerevisiae / Q000032:analysis*; D013912:Threonine
chemical_list: D009843:Oligoribonucleotides; D012265:Ribonucleotides; D013912:Threonine; D012343:RNA, Transfer; D006163:Ribonuclease T1
vernacular_title: Structure primaire des tRNA Thr 1a et b de levure de bière.