6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu - - 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu a two-step reaction , in the first step, the enzyme condenses the cognate amino acid and ATP, forming an aminoacyl-adenylate intermediate with a diphosphate as the leaving group. This reaction is reversible in the absence of the tRNA. In the absence of tRNAGlu, ATP binding by GluRS is nonproductive because the alpha-phosphate of ATP and the alpha-carboxyl groups of Glu are positioned too far apart for a reaction to occur. The presence of tRNAGlu causes conformational changes surrounding the ATP binding site, allowing ATP to bind in the productive state, which moves the alpha-phosphate of the ATP closer to the alpha-carboxyl groups of Glu, allowing the reaction for the formation of the glutamyl-AMP intermediate to occur -, 745395 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu aminoacylation reaction via a two-step mechanism involving a very unstable aa-AMP intermediate 746179 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu ATP and tRNAGlu bind randomly to the free enzyme, whereas glutamate binds only to the ternary enzyme-tRNAGlu-ATP complex. After interconversion of the quarternary enzyme-substrate complex the end-products dissociate in the order: diphosphate, AMP, Glu-tRNA 220 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu catalytic site structure, substrate binding and reaction mechanism 651000 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu concerted mechanism 212 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu random binding of ATP and L-glutamate to the enzyme-tRNA complex -, 703636 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu the major recognition element of the tRNAGlu is U at position 34 651055 6.1.1.17 ATP + L-glutamate + tRNAGlu = AMP + diphosphate + L-glutamyl-tRNAGlu the transfer of amino acid to tRNA is accompanied by the protonation of AMP to H-AMP. Subsequent migration of proton to water reduces the stability of the complex and loosens the interface both in the presence and in the absence of AMP. The subsequent undocking of AMP or tRNA then proceeds along thermodynamically competitive pathways. Release of the tRNA acceptor stem is further accelerated by the deprotonation of the alpha-ammonium group on the charging amino acid. The proposed general base is Glu41 705182