- Synthesis of non-hydrolyzable substrate analogs for Asp-tRNAAsn/Glu-tRNAGln amidotransferase
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Non-hydrolyzable substrate analogs for tRNA-dependent amidotransferase, 2′- or 3′-aspartyl or -glutamyl adenosine, were synthesized from adenosine without protection of the adenine base. The hydroxyl groups of adenosine were selectively protected, followed by a series of oxidation/reductions to alter the stereochemistry. DFT calculations revealed the driving forces for the ketone hydrate formation at C-2′, but not the C-3′ carbon during the oxidation step. Subsequently, triflation and azide replacement yielded azidoadenosines, which were coupled to protected amino acids after deprotection and reduction. After global deprotection, the target substrate analogs were obtained in 2-14% overall yields from adenosine.
- Klinchan, Chayada,Hsu, Yu-Ling,Lo, Lee-Chiang,Pluempanupat, Wanchai,Chuawong, Pitak
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supporting information
p. 6204 - 6207
(2014/12/10)
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- Direct PCR amplification of various modified DNAs having amino acids: Convenient preparation of DNA libraries with high-potential activities for in vitro selection
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We synthesized modified 2′-deoxyuridine triphosphates bearing amino acids at the C5 position and investigated their substrate properties for KOD Dash DNA polymerase during polymerase chain reaction (PCR). PCR using C5-modified dUTP having an amino acyl group (arginyl, histidyl, lysyl, phenylalanyl, tryptophanyl, leucyl, prolyl, glutaminyl, seryl, O-benzyl seryl or threonyl group) gave the corresponding full-length PCR products in good yield. Although dUTP analogues bearing aspartyl, glutamyl or cysteinyl were found to be poor substrates for PCR catalyzed by KOD Dash DNA polymerase, optimization of the reaction conditions resulted in substantial generation of full-length product. In the case of reaction using dUTP analogue having a cysteinyl group, addition of a reducing agent improved the reaction yield. Thus, PCRs using KOD Dash DNA polymerase together with amino acyl dUTP provide convenient and efficient preparation of various modified DNA libraries with potential protein-like activities.
- Kuwahara, Masayasu,Hanawa, Kazuo,Ohsawa, Kazuomi,Kitagata, Rina,Ozaki, Hiroaki,Sawai, Hiroaki
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p. 2518 - 2526
(2007/10/03)
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- Synthesis of γ-Glutamyl Peptides Catalyzed by Transamidase from Bacillus natto
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Crude ammonium sulfate fraction of a cell free extract from Bacillus natto contained an enzyme (or enzymes) which catalyzed the transamidation reaction specific for glutamine.Both L- and D-isomers of glutamine were active as substrate.On incubation of L- or D-glutamine with the enzyme preparation, two peptides consisting of glutamic acid and glutamine were formed.The main component of the peptides was readily isolated by ion-exchange chromatography and identified as γ-glutamylglutamine by paper chromatography and by paper electrophoresis using authentic peptides.The optical configuration of the amino acid residues in the dipeptide was determined by digestion of the acid hydrolyzate with L-glutamic acid decarboxylase, and the result showed that the dipeptide obtained from L-glutamine was a L-L isomer, while the dipeptide from D-glutamine was a D-D isomer.
- Noda, Kosaku,Igata, Keiko,Horikawa, Yoshiko,Fujii, Hisao
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p. 2419 - 2424
(2007/10/02)
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