33043-58-2Relevant academic research and scientific papers
Mechanism of N6-threonylcarbamoyladenonsine (t6A) biosynthesis: Isolation and characterization of the intermediate threonylcarbamoyl-AMP
Lauhon, Charles T.
, p. 8950 - 8963 (2013/01/15)
Genetic and biochemical studies have recently implicated four proteins required in bacteria for the biosynthesis of the universal tRNA modified base N6-threonylcarbamoyl adenosine (t6A). In this work, t6A biosynthesis in Bacillus subtilis has been reconstituted in vitro and found to indeed require the four proteins YwlC (TsaC), YdiB (TsaE), YdiC (TsaB) and YdiE (TsaD). YwlC was found to catalyze the conversion of l-threonine, bicarbonate/CO2 and ATP to give the intermediate l-threonylcarbamoyl- AMP (TC-AMP) and pyrophosphate as products. TC-AMP was isolated by HPLC and characterized by mass spectrometry and 1H NMR. NMR analysis showed that TC-AMP decomposes to give AMP and a nearly equimolar mixture of l-threonine and 5-methyl-2-oxazolidinone-4-carboxylate as final products. Under physiological conditions (pH 7.5, 37 °C, 2 mM MgCl2), the half-life of TC-AMP was measured to be 3.5 min. Both YwlC (in the presence of pyrophosphatase) and its Escherichia coli homologue YrdC catalyze the formation of TC-AMP while producing only a small molar fraction of AMP. This suggests that CO2 and not an activated form of bicarbonate is the true substrate for these enzymes. In the presence of pyrophosphate, both enzymes catalyze clean conversion of TC-AMP back to ATP. Purified TC-AMP is efficiently processed to t6A by the YdiBCE proteins in the presence of tRNA substrates. This reaction is ATP independent in vitro, despite the known ATPase activity of YdiB. The estimated rate of conversion of TC-AMP by YdiBCE to t6A is somewhat lower than the initial rate from l-threonine, bicarbonate and ATP, which together with the stability data, is consistent with previous studies that suggest channeling of this intermediate.
ENANTIOMERIC QUANTIFICATIONS OF AMINO ACIDS THROUGH THEIR Nα-ACYL AMIDES BY GAS CHROMATOGRAPHY.
Hosten, N.,Anteunis, M. J. O.
, p. 45 - 47 (2007/10/02)
Apparent separation of 1.1 or higher on Chiralsil Val III can be obtained for Nα-acyl N-alkyl aminoacid amides allowing the use of short capillary gas chromatographic columns.A clean derivatization protocol without racemization is described, proceding through the NCA derivatives that are prepared from "in situ" silylated amino acids with trimethylsilyl cyanide.
