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The oligonucleotide stimulated binding of yeast Tyr­tRNA and yeast Lys­tRNA to yeast ribosomes has been studied. Yeast Tyr­tRNA bound strongly to both yeast and Escherichia coli ribosomes with U-A-U and U-A-C, and less well with U-A-A. The binding observed with U-A-A was further investigated. [3H]U-A-A binds to ribosomes in the presence of yeast tRNA fractions containing tRNATyr. Yeast Tyr­tRNA did not cause incorporation of tyrosine at UAA codons in the E. coli system. Yeast Lys­tRNA bound to both yeast and E. coli ribosomes in the presence of A-A-A, A-A-G, G-A-G, and U-A-G with a lower magnesium ion requirement for binding. Yeast Met­tRNA had binding properties similar to those of E. coli Met­tRNA. [ABSTRACT FROM AUTHOR]

32P-labelled N-formyl methionyl transfer RNA from Escherichia coli strain CA265 was purified by chromatography on a column DEAE Sephadex followed by chromatography on benzoylated DEAE cellulose. Nucleotides from ribonuclease T1 and pancreatic ribonuclease digests of tRNAF were separated and their sequences determined. tRNAF consists of 77 nucleotides of which pCG is 5′-terminal and CAACCOH is 3′-terminal. [ABSTRACT FROM AUTHOR]

We have devised a simplified method for the purification of the bacterial initiator tRNA, tRNAfMet in amounts greater than 100 mg from 10 g of unfractionated tRNA. The purification of the normal methionine tRNA, tRNAmMet, was also achieved but with a lower yield. During the fractionation studies we identified two chromatographically separable species of tRNAfMet and two of tRNAmMet. The triplet binding assay did not differentiate between fMet-tRNAf1 and fMet-tRNAr2 or between Met-tRNAm1 and Met-tRNAm2. An anticodon containing fragment of tRNAmMet did not inhibit the charging of tRNAfMet or of tRNAmMet under conditions where it should behave as a linear sequence of nucleotides. Both tRNAfMet and tRNAmMet contain approximately one mole of £he minor nucleoside, 4-thiouridine, per mole of tRNA. In our functional tests the presence of 4-thiouridine was not necessary for the biological activity of tRNAfMet. [ABSTRACT FROM AUTHOR]