Question

In E. coli, tRNAs are synthesized as large precursor tRNAs that must be cleaved to produce mature, functional tRNAs that carry amino acids. The processing of precursor tRNA molecules typically involves an endonuclease called ______, and an exonuclease called ______.

Answer 1

In E. coli, tRNA precursors are processed by RNase P and RNase D to become mature tRNAs, involving trimming and methylation for stability.

Step-by-step explanation:

In E. coli, tRNAs are synthesized as large precursor tRNAs that must be cleaved to produce mature, functional tRNAs that carry amino acids. The processing of precursor tRNA molecules typically involves an endonuclease called RNase P, and an exonuclease called RNase D.

tRNA molecules undergo a series of processing steps after transcription. Pre-tRNA molecules, like their rRNA counterparts, are initially part of larger transcripts that need to be trimmed and modified to become fully functional. During this processing, specific nucleotide sequences are removed, and the molecules undergo methylation, which involves the addition of a -CH3 moiety (methyl functional group) for stability.

The correct folding into their characteristic three-dimensional structures is also essential for the functionality of tRNAs, allowing them to carry the correct amino acids and recognize the appropriate codons during protein synthesis.