Interaction of Fragmented and Cross-Linked Escherichia coli Valine Transfer Ribonucleic Acid with Tu Factor-Guanosine Triphosphate Complex

Abstract

The structural requirements for recognition between T,-GTP and aminoacyl-tRNA have been studied with Escherichia co2i T, factor and purified E. coli valine tRNA.Cleavage of tRNAV"' at the anticodon into 2 half-molecules, followed by recombmation and charging with valine, yielded a functional complex, showing that an intact anticodon is not necessary for T,-GTP recognition.Testing of valyl-tRNA(3'), that is, valine esterified to only the 3' half of the molecule, showed that this structure was insufficient for reactivity, leading to the conclusion that recognition requires more structure than is provided by an aminoacylated 3' half-molecule.Crosslinking of the dihydrouridine-containing and amino acid acceptor arms by the covalent joining of 4-thiouridine and cytidine did not affect T,-GTP recognition, showing that this constraint on conformation freedom also is not important.