Studies on T. utilis tRNATyr variants with enzymatically altered D-loop sequences. I. Deletion of the conserved sequence Gm-G and its effects on aminoacylation and conformation.
Variants of T. utilis tRNATyr containing deletions or substitutions of nucleotides in the D-loop region have been prepared by several enzymatic reaction steps in vitro. Although these variants lack the "conserved" nucleotides Gm18-G19 in their D-loop, their tyrosine-accepting capacities are indistinguishable from that of the native tRNATyr. Thermal denaturation studies with tRNATyr variants lacking the Gm18-G19 sequence have revealed a biphasic nature of the melting profile, suggesting the loss of tertiary interactions between Gm18-G19 and somewhere in the molecule (probably in the T psi C-loop region). These results indicate that nucleotide sequences around Gm18-G19 (i.e. D16-D-Gm-G19 or Gm18-G-D-D21) themselves are not essential sites for the recognition of tRNATyr by T. utilis tyrosyl-tRNA synthetase and that tRNATyr variants with an apparently "relaxed" conformation still have full aminoacylation capacities at around 30 degrees C.
D000215:Acylation; D000469:Alkaline Phosphatase / Q000378:metabolism; D001483:Base Sequence; D002175:Candida / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D006358:Hot Temperature; D007700:Kinetics; D009690:Nucleic Acid Conformation; D009691:Nucleic Acid Denaturation; D011116:Polynucleotide 5'-Hydroxyl-Kinase / Q000378:metabolism; D011130:RNA Ligase (ATP) / Q000378:metabolism; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D006163:Ribonuclease T1 / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D012346:RNA, Transfer, Amino Acyl; D014443:Tyrosine; D011116:Polynucleotide 5'-Hydroxyl-Kinase; D006163:Ribonuclease T1; D000469:Alkaline Phosphatase; D011130:RNA Ligase (ATP)