J. Biochem, 1982, Vol. 91, No. 4 1241-1248
© 1982 Japanese Biochemical Society
research-article |
The Nucleotide Sequence and Codon Recognition of Proline tRNA fromTorulopsis utilis
Institute of Molecular Biology, School of Science, Nagoya University Chikusa-ku, Nagoya, Aichi 464
Proline tRNA from Torulopsis (Candida) utilis was purified by chromatography on columns of DEAE-Sephadex A-50 at pH 7.6 and 4.0, DEAE-Sephadex A-50 at pH 6.0, and RPC-5 at pH 4.0. This tRNA was sequenced by combining conventional chromatographic methods with rapid read-out chemical and enzymatic gel sequencing methods. The tRNA consists of 75 nucleotides and has the following sequence: pG-G-C-Cm-G-C-G-U-m1-G-G-U-C-
-A-G-D-G-G-D-A-U-A-C-U-C-U-C-G-C-U-U-N-G-G-m1-G-
-G-
-G-A-G-U-G-7-D-,m5-m5C-A-G-G-G-T-
-C-A-m1A-U-U-C-C-C-U-G-C-U-C-G-G-C-C-C-C-C-A. An unknown nucleotide in the first position of the anticodon was shown to be an uridine derivative by UV-spectrum, mobility on thin-layer chromatogram, and preliminary measurement of NMR spectrum. The specificity of this tRNA for codon recognition was studied by the ribo-somal binding technique. Three out of four proline codons were recognized: CCA and CCU preferentially, and CCC weakly. Unexpectedly, CCG failed to bind this tRNA to ribosomes.
1Present address: Department of Cellular and Developmental Biology, University of Arizona, Tucson, Arizona 85721, U.S.A.