Role of the CCA end of tRNA and its vicinity in aminoacylation.
The CCA sequence is common to all the 3' ends of tRNAs and more than half of the tRNAs possess the G1C72 base pair at the end of acceptor stem. To study the role of these terminal trinucleotides and their vicinity in the aminoacylation process, not only the substitutions of these bases but also the nucleotide-additions at the 5' end of tRNA were introduced into many kinds of Escherichia coli tRNA transcripts and the effects on the aminoacylation activity with cognate aminoacyl-tRNA synthetase were investigated. Basically the requirement of the CCA sequence in aminoacylation differed among each amino acid specific tRNA. Some rough conclusions could be drawn from the present results. It was found that the G1C72 base pair functioned as the negative identity elements in many tRNAs. The nucleotide-addition experiments suggested that proper spatial arrangement and flexibility were important for aminoacylation reaction. Functional and evolutional implications of the invariant CCA sequence and its vicinity were discussed.
Tamura
K
K
Biophysical Chemistry Laboratory, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
Hasegawa
T
T
D001483:Base Sequence; D004926:Escherichia coli / Q000378:metabolism; D012329:RNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry* / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000737:chemistry / Q000378:metabolism*
D012329:RNA, Bacterial; D012346:RNA, Transfer, Amino Acyl; D012343:RNA, Transfer