Transacylation rates of (aminoacyl)adenosine moiety at the 3'-terminus of aminoacyl transfer ribonucleic acid. 1983

M Taiji, and S Yokoyama, and T Miyazawa

The rates of migration of the aminoacyl group (transacylation) between 2'-O-(aminoacyl)-tRNA and 3'-O-(aminoacyl)-tRNA were studied by the nuclear magnetic resonance (NMR) analyses of 3'-terminal fragment models, with regard to the significance of transacylation in the process of protein biosynthesis. 2'(3')-O-L-Alanyladenosine, -valyladenosine, -isoleucyladenosine, -phenylalanyladenosine, and -methionyladenosine, and 2'(3')-O-L-phenylalanyladenosine 5'-phosphate and methionyladenosine 5'-phosphate were chemically synthesized, and the rates of transacylation in deuterated buffer were directly measured by the NMR saturation transfer method. The dependences of transacylation rates on p2H and temperature were analyzed. The results indicate that the transacylation rates are significantly affected by the ionization states of the alpha-amino group of the amino acid moiety but not by the presence of the 5'-phosphate group of the adenylate moiety. The second-order rate constants for the base-catalyzed transacylation reactions were also determined for the ionized form (with alpha-N2H3+ group) of (aminoacyl)adenosines. The transacylation rates of (aminoacyl)adenosines in 1H2O solution at p1H 7.3 and 37 degrees C (intracellular environment) were evaluated as 3-11 s-1 for the 2' leads to 3' transacylation and 1-4 s-1 for the 3' leads to 2' transacylation, indicating that the transacylation rate of free aminoacyl-tRNA is slower than the overall rate of polypeptide chain elongation per ribosome. This suggests the presence of some enzymatic factor for enhancing the transacylation rates of aminoacyl-tRNAs in the polypeptide chain elongation process in vivo.

UI MeSH Term Description Entries
D007536 Isomerism The phenomenon whereby certain chemical compounds have structures that are different although the compounds possess the same elemental composition. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed) Isomerisms
D007700 Kinetics The rate dynamics in chemical or physical systems.
D009682 Magnetic Resonance Spectroscopy Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING). In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D009690 Nucleic Acid Conformation The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape. DNA Conformation,RNA Conformation,Conformation, DNA,Conformation, Nucleic Acid,Conformation, RNA,Conformations, DNA,Conformations, Nucleic Acid,Conformations, RNA,DNA Conformations,Nucleic Acid Conformations,RNA Conformations
D010710 Phosphates Inorganic salts of phosphoric acid. Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D000107 Acetylation Formation of an acetyl derivative. (Stedman, 25th ed) Acetylations
D000241 Adenosine A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter. Adenocard,Adenoscan
D012346 RNA, Transfer, Amino Acyl Intermediates in protein biosynthesis. The compounds are formed from amino acids, ATP and transfer RNA, a reaction catalyzed by aminoacyl tRNA synthetase. They are key compounds in the genetic translation process. Amino Acyl tRNA,Transfer RNA, Amino Acyl,tRNA-Amino Acyl,Amino Acyl T RNA,Acyl tRNA, Amino,Acyl, tRNA-Amino,tRNA Amino Acyl,tRNA, Amino Acyl
D013329 Structure-Activity Relationship The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups. Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D013696 Temperature The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms. Temperatures

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