Which mechanism is primarily associated with the proofreading process in RNAP?

The proofreading process in RNA polymerase (RNAP) relies mainly on hydrolysis, which is the breakdown of nucleotides to ensure accurate RNA transcription. During transcription, RNAP adds nucleotides to the growing RNA strand, but occasionally, it incorporates the wrong nucleotide.

When a mismatch occurs, the RNAP can recognize this error. Hydrolysis plays a critical role by allowing the enzyme to cleave the incorrectly paired nucleotide from the RNA strand. Once this detection and removal happen, RNAP can reinitiate the transcription process correctly by adding the right nucleotide. This mechanism enhances the fidelity of RNA synthesis, making it a crucial aspect of the proofreading function.

In contrast, phosphorylation and dephosphorylation are processes generally involved in the regulation of protein function and activity but are not directly linked to the proofreading aspect of RNA synthesis. Polyadenylation pertains to the addition of a poly(A) tail to mRNA and is a separate post-transcriptional modification not involved in proofreading errors during transcription.