scholarly journals Studies on transfer ribonucleic acids and related compounds. XXXIX. Chemical synthesis of heptadeca- and hexadecaribonucleotides corresponding to the 3'-terminus of the tRNAfMet of E. coli.

1981 ◽  
Vol 29 (10) ◽  
pp. 2799-2806 ◽  
Author(s):  
EIKO OHTSUKA ◽  
KAZUO FUJIYAMA ◽  
TOSHIKI TANAKA ◽  
MORIO IKEHARA
Keyword(s):  
Chemical Synthesis ◽  
Ribonucleic Acids ◽  
E Coli ◽  
Related Compounds

scholarly journals Studies on transfer ribonucleic acids and related compounds. XXI. Synthesis and properties of guanine rich fragments from E. coli tRNAfMet 5'-end.

1978 ◽  
Vol 26 (10) ◽  
pp. 2998-3006 ◽  
Author(s):  
EIKO OHTSUKA ◽  
EIKO NAKAGAWA ◽  
TOSHIKI TANAKA ◽  
ALEXANDERF. MARKHAM ◽  
MORIO IKEHARA
Keyword(s):  
Ribonucleic Acids ◽  
E Coli ◽  
Related Compounds

scholarly journals Radical Dehalogenation and Purine Nucleoside Phosphorylase E. coli: How Does an Admixture of 2′,3′-Anhydroinosine Hinder 2-fluoro-cordycepin Synthesis

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 539
Author(s):  
Alexey L. Kayushin ◽  
Julia A. Tokunova ◽  
Ilja V. Fateev ◽  
Alexandra O. Arnautova ◽  
Maria Ya. Berzina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Chemical Synthesis ◽  
Purine Nucleoside Phosphorylase ◽  
Purine Nucleoside ◽  
Preparative Synthesis ◽  
Nucleoside Phosphorylase ◽  
E Coli ◽  
First Time

During the preparative synthesis of 2-fluorocordycepin from 2-fluoroadenosine and 3′-deoxyinosine catalyzed by E. coli purine nucleoside phosphorylase, a slowdown of the reaction and decrease of yield down to 5% were encountered. An unknown nucleoside was found in the reaction mixture and its structure was established. This nucleoside is formed from the admixture of 2′,3′-anhydroinosine, a byproduct in the preparation of 3-′deoxyinosine. Moreover, 2′,3′-anhydroinosine forms during radical dehalogenation of 9-(2′,5′-di-O-acetyl-3′-bromo- -3′-deoxyxylofuranosyl)hypoxanthine, a precursor of 3′-deoxyinosine in chemical synthesis. The products of 2′,3′-anhydroinosine hydrolysis inhibit the formation of 1-phospho-3-deoxyribose during the synthesis of 2-fluorocordycepin. The progress of 2′,3′-anhydroinosine hydrolysis was investigated. The reactions were performed in D2O instead of H2O; this allowed accumulating intermediate substances in sufficient quantities. Two intermediates were isolated and their structures were confirmed by mass and NMR spectroscopy. A mechanism of 2′,3′-anhydroinosine hydrolysis in D2O is fully determined for the first time.

scholarly journals Evidence that the metabolite repair enzyme NAD(P)HX epimerase has a moonlighting function

2018 ◽  
Vol 38 (3) ◽  
Author(s):  
Thomas D. Niehaus ◽  
Mona Elbadawi-Sidhu ◽  
Lili Huang ◽  
Laurence Prunetti ◽  
Jesse F. Gregory ◽  
...  
Keyword(s):  
Vitamin B6 ◽  
Weakly Bound ◽  
E Coli ◽  
Essentially Normal ◽  
Metabolite Repair ◽  
Mutant Cells ◽  
Dehydratase Activity ◽  
Related Compounds

NAD(P)H-hydrate epimerase (EC 5.1.99.6) is known to help repair NAD(P)H hydrates (NAD(P)HX), which are damage products existing as R and S epimers. The S epimer is reconverted to NAD(P)H by a dehydratase; the epimerase facilitates epimer interconversion. Epimerase deficiency in humans causes a lethal disorder attributed to NADHX accumulation. However, bioinformatic evidence suggest caution about this attribution by predicting that the epimerase has a second function connected to vitamin B6 (pyridoxal 5′-phosphate and related compounds). Specifically, (i) the epimerase is fused to a B6 salvage enzyme in plants, (ii) epimerase genes cluster on the chromosome with B6-related genes in bacteria, and (iii) epimerase and B6-related genes are coexpressed in yeast and Arabidopsis. The predicted second function was explored in Escherichia coli, whose epimerase and dehydratase are fused and encoded by yjeF. The putative NAD(P)HX epimerase active site has a conserved lysine residue (K192 in E. coli YjeF). Changing this residue to alanine cut in vitro epimerase activity by ≥95% but did not affect dehydratase activity. Mutant cells carrying the K192A mutation had essentially normal NAD(P)HX dehydratase activity and NAD(P)HX levels, showing that the mutation had little impact on NAD(P)HX repair in vivo. However, these cells showed metabolome changes, particularly in amino acids, which exceeded those in cells lacking the entire yjeF gene. The K192A mutant cells also had reduced levels of ‘free’ (i.e. weakly bound or unbound) pyridoxal 5'-phosphate. These results provide circumstantial evidence that the epimerase has a metabolic function beyond NAD(P)HX repair and that this function involves vitamin B6.

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