Aminoacyl nucleosides. VII. N-(purin-6-ylcarbamoyl)threonine. A new component of transfer ribonucleic acid

Diversity of the biosynthesis pathway for threonylcarbamoyladenosine (t6A), a universal modification of tRNA

“…12 The hypermodified base t 6 A is present in nearly all ANN decoding tRNAs and has been studied in vitro and in vivo for more than 40 y. [13][14][15][16][17][18][19] Since the first discovery of the modification by Schweizer, et al in 1969, 18 sporadic studies established the basic requirements for the synthesis of this universal modification, identifying the requirement for ATP, threonine and carbonate, 15,17,[20][21][22] but fell short of elucidating the multi-step path to its formation. Subsequent studies in which native E. coli tRNA fMet (harboring an unmodified A 37 ) and yeast tRNA iMet transcripts were converted to t 6 A 37 after microinjection into Xenopus laevis oocytes demonstrated that the formation of t 6 A occurred in the oocyte cytoplasm and used a conserved machinery.…”

The Levels of a Universally Conserved tRNA Modification Regulate Cell Growth

“…It stabilizes codon-anticodon interaction (13), suggesting that t 6 A might have a role regulating protein synthesis initiation. The modification was discovered over 40 years ago (14), but the enzymes involved in t 6 A synthesis were only identified and characterized in all domains of life in the last few years (15)(16)(17)(18)(19)(20)(21) and recently renamed (22). In yeast, components of the threonyl-carbamoyl transferase complex (TCTC, previously named KEOPS/EKC (kinase, endopeptidase and other proteins of small size/endopeptidase-like and kinase associated to transcribed chromatin) are required for t 6 A synthesis.…”

The structure of the rubidium salt of N-(purin-6-ylcarbamoyl)-L-threonine tetrahydrate, a hypermodified base in the anticodon loop of some tRNA's

“…As this hydrogen bonding probably occurs in solution (n.m.r. data: Schweizer, Chheda, Baczynskyj & Hall, 1969) it may be important in anticodon loop conformation and may lead to a revision of current views on the structure of cytokinine ureidopurines (Dyson, Hall, Hong, Dutta & Chheda, 1972). There is a possibility that the hydrogen bond is bifurcated as the distance O(19)-N(12) is 2.783 A.…”