The nucleotide sequence of cysteine transfer ribonucleic acid from baker''s yeast. Products of complete digestion with pancreatic ribonuclease and ribonuclease T1.

1.The nucleotide chain of tRNA Cys from baker's yeast was readily split at the anticolon into two large fragments by brief treatment with ribonuclease T1.2. The whole molecule and the two derived large fragments were completely digested with (a) pancreatic ribonuclease and (b) ribonuclease T1. The fragments present in each of the digests were separated and sequenced by conventional methods. 3. The groups of fragments derived from the two methods of digestion were entirely compatible with each other. 4. The molecule is 75 nucleotides long, but, as isolated, lacks the terminal adenosine and the neighboring cytidylic acid residue. The minor nucleotides 1-methyladenylic acid, 7-methylguanylic acid, 5-methylcytidylic acid and N6 (gamma gamma-dimethylallyl)adenylic acid (isopentenyladenylic acid) were identified.     

The extraction and purification of a cysteine transfer ribonucleic acid from baker''s yeast.

1. A modification of the RPC 1 system of A.D. Kelmers, G.D. Novelli & M.P. Stulberg (1965) (J. Biol. Chem. 240, 3979-3983) is described in which the support medium is a Celite of narrow range particle size treated with dichlorodimethylsilane. 2. By using this system an apparently pure preparation of tRNA Cys was isolated from baker's yeast tRNA. 3. This preparation accepted at least 60% of the theoretical quantity of [3-14C]cysteine in a conventional assay and failed to accept isoleucine, phenylalanine, proline, serine or tyrosine. 4. A theoretical countercurrent-distribution curve calculated by assuming a distribution coefficient K of 2.03 was in excellent agreement with the profiles of E260 and cysteine-acceptor ability after 537 transfers in the 1.85 M-phosphate/formamide/propan-2-ol system of C.M. Connelly & B.P. Doctor (1965) (J. Biol. Chem. 241, 715-719). 5. Chromatography of tRNA Cys on Bio-Gel P100 polyacrylamide beads afforded two components one of which was far less efficient than the other in accepting cysteine. The base compositions of the two were similar.     

The corrected nucleotide sequence of yeast leucine transfer ribonucleic acid

The nucleotide sequence of “Renaturable” leucine transfer RNA from Baker's yeast has been re-investigated. The results showed that (i) this tRNA has a sequence of DCD at positions 19–21, (ii) it has an anticodon m⁵CAA and (iii) it has a pseudouridine at position 40.     

The primary nucleotide sequence of nuclear U-2 ribonucleic acid. The 5'-terminal portion of the molecule.

The nuclear U-2 RNA which is highly modified (Reddy, R., Ro Choi, T.S., Henning, D., Shibata, H., Choi, Y.C., and Busch H. (1972) J. Biol. Chem. 247, 7245-7250) contains 13 pseudouridylic acid residues, 10 2'-O-methylated nucleotides and two modified bases including N-2,2, 7-trimethyl guanylic acid in its 5'-terminal portion (69 nucleotides). With the determination of this sequence and its overlap with the 3' portion of the molecule (nucleotides 70 to 196), the over-all nucleotide sequence of this RNA is:(see article). The concentration of modified nucleotides in its 5' portion is greater than for any RNA sequenced thus far.     

Messenger ribonucleic acid of the lipoprotein of the Escherichia coli outer membrane. II. The complete nucleotide sequence

The complete nucleotide sequence of the mRNA for the outer membrane lipoprotein from Escherichia coli has been determined. All the ribonuclease T1 and ribonuclease A fragments obtained from the mRNA were connected with DNA sequencing of restriction endonuclease fragments of the cloned lipoprotein gene. The mRNA consists of 322 nucleotides, and there are 38 and 50 nucleotides in the 5' and 3' end untranslated regions, respectively. The mRNA has several unique features: (a) Out of 50 possible codons for 15 amino acids in the prolipoprotein only 25 codons are used, and all of these appear to be read by the major isoaccepting species of tRNAs for individual amino acids. (b) In the first 64 nucleotides from the 5' end, there are no obvious secondary structures. On the other hand, between the 65th nucleotide and the 3' end, 85% of the nucleotides are involved in the formation of secondary structures, with nine stable stem-and-loop structures. (c) There are many repeating sequences including one repeat of 40 nucleotides. (d) There are a few other features which could be important for efficient translation of the mRNA.