The syn-Oriented 2-OH Provides a Favorable Proton Transfer Geometry in 1,2-Diol Monoester Aminolysis:Implications for the Ribosome Mechanism

摘要

1,2-Diol monoester aminolysis,the iteration of which on the living cell ribosome results in protein biosynthesis,is a fundamental chemical reaction.A neighboring 2-OH has a small effect on ester reactivity in aqueous solutions,but this effect increases strongly in non-hydrogen bonding solvents.The importance of the 2'-OH of the invariant peptidyl tRNA 3'-terminal adenosine now seems well established,but the nature of its catalysis is less clear.The simplest model reaction of the 1,2-diol monoester aminolysis is the ammonolysis of 1-O-formyl 1,2-ethanediol 1(Scheme 1).Previous computational studies of the transition state structures and energetics of the aminolysis of its 2-deoxy derivatives revealed two reaction pathways or mechanisms viable in the gas phase/ aprotic medium.