Domain movements during CCA-addition: a new function for motif C in the catalytic core of the human tRNA nucleotidyltransferases.

ABSTRACT: CCA-adding enzymes are highly specific RNA polymerases that synthesize and maintain the sequence CCA at the tRNA 3'-end. This nucleotide triplet is a prerequisite for tRNAs to be aminoacylated and to participate in protein biosynthesis. During CCA-addition, a set of highly conserved motifs in the catalytic core of these enzymes is responsible for accurate sequential nucleotide incorporation. In the nucleotide binding pocket, three amino acid residues form Watson-Crick-like base pairs to the incoming CTP and ATP. A reorientation of these templating amino acids switches the enzyme's specificity from CTP to ATP recognition. However, the mechanism underlying this essential structural rearrangement is not understood. Here, we show that motif C, whose actual function has not been identified yet,

SUBMITTER: Ernst FG 

PROVIDER: S-EPMC4615804 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature