| Autor: |
Kingery DA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA., Pfund E, Voorhees RM, Okuda K, Wohlgemuth I, Kitchen DE, Rodnina MV, Strobel SA |
| Jazyk: |
angličtina |
| Zdroj: |
Chemistry & biology [Chem Biol] 2008 May; Vol. 15 (5), pp. 493-500. |
| DOI: |
10.1016/j.chembiol.2008.04.005 |
| Abstrakt: |
The ribosome has an active site comprised of RNA that catalyzes peptide bond formation. To understand how RNA promotes this reaction requires a detailed understanding of the chemical transition state. Here, we report the Brønsted coefficient of the alpha-amino nucleophile with a series of puromycin derivatives. Both 50S subunit- and 70S ribosome-catalyzed reactions displayed linear free-energy relationships with slopes close to zero under conditions where chemistry is rate limiting. These results indicate that, at the transition state, the nucleophile is neutral in the ribosome-catalyzed reaction, in contrast to the substantial positive charge reported for typical uncatalyzed aminolysis reactions. This suggests that the ribosomal transition state involves deprotonation to a degree commensurate with nitrogen-carbon bond formation. Such a transition state is significantly different from that of uncatalyzed aminolysis reactions in solution. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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