Aminoacyl nucleosides. VI. Isolation and preliminary characterization of threonyladenine derivatives from transfer ribonucleic acid

Abstract

Transfer ribonucleic acid was hydrolyzed by acid under conditions that released the purine residues. Examination of the hydrolysate by means of ion-exchange chromatography on a sulfonic acid resin revealed the presence of a A number of articles reports the presence of amino acids or small polypeptides, apart from the amino acids attached to the acceptor end of tRNA molecules, bound to nucleic acids. Ingram and Sullivan (1962) and Akashi et al. (1965), for example, have reported the presence of amino acids bound to RNA which cannot be removed through the use of extensive deproteinizing procedures. Balk et al. (1964) and Olenick and Hahn (1964) have reported the presence of amino acids in highly purified preparations of DNA isolated from a variety of sources. The nature of the amino acid-nucleic acid linkage, however, has not been elucidated. Bogdanov et al. (1962) have reported that tRNA contains amino acids attached to the phosphate residues. Harris and Wiseman (1962) have also reported the presence of small polypeptides attached to the

Enzymic synthesis of N-(purin-6-ylcarbamoyl)threonine, an anticodon-adjacent base in transfer ribonucleic acid

“…Taking the value for the normal t6A content of E . coli tRNA as 0.07 mo1/100 mol of nucleotides (Chheda et al, 1969), 33% of this would be 0.023 mol/ 100 mol of nucleotides theoretical acceptor activity. The actual incorporation gave only 0.003 mo1/100 mol of nucleotides or 13% of the theoretical value.…”

“…Chheda et ai. (1969) and Schweizer et al (1969) found that tbA in mild alkali (0.2 M N H 4 0 H ) rearranges to release the carbonylthreonine fragment from the adenine in the form of an internal urethane; Le., 5-methyl-2-oxooxazblidine-4-carboxylic acid. A separate experiment was therefore run to determine the alkali lability of the enzymatically synthesized t6A.…”

“…structure of this nucleoside was determined by Chheda er al. (1969) and Schweizer et al (1969) The simpler trivial name N 6 -( N -threonylcarbony1)adenosine which has been suggested for this nucleoside' more clearly indicates the derivation of its components from threonine, CO2, and adenosine which is the subject of this paper. The base of this nucleoside has the systematic name N -(purin-6-y1carbamoyl)threonine (t6Ade) or the trivial name N 6 -( N -threonylcarbony1)adenine.…”

“…The labeled tRNA was dissolved in 0.5 ml of water, and 0.5 ml of 2 IC HCI was added. The solution was heated for 15 min in a boiling water bath to release purines including the labeled t6Ade from the t R N A (Chheda et al, 1969). The resulting solution was flash evaporated, water was added, it was flash evaporated again, and this was repeated once more to remove all traces of HCI.…”

In vitro biosynthesis of a universal t6A tRNA modification in Archaea and Eukarya

“…t 6 A modification has been discovered, and its chemical structure was elucidated >40 years ago (9). Initial studies of t 6 A biosynthesis performed in vivo or with Escherichia coli cellular extracts demonstrated that the reaction required adenosine triphosphate (ATP), carbonate, magnesium and threonine (10,11).…”