Metal ion requirement for catalysis by 3'-5' RNA polymerases.

ABSTRACT: The two-metal ion mechanism for catalysis of RNA and DNA synthesis by 5'-3' polymerases has been extensively characterized. The 3'-5' polymerase family of enzymes, consisting of tRNA^His guanylyltransferase (Thg1) and Thg1-like proteins (TLPs), perform a similar nucleotide addition reaction, but in the reverse direction, adding Watson-Crick base paired NTPs to the 5'-ends of RNA substrates, yet the effect of divalent cations beyond magnesium has not been described. Here, we examined the effects of five divalent cations (Mg²⁺, Mn²⁺, Co²⁺, Ni²⁺ and Ca²⁺) on templated nucleotide addition activity and kinetics of 5'-activation by ATP catalyzed by recombinantly purified, metal-free TLPs from organisms from diverse domains of life.

SUBMITTER: Iwaniec BWJ 

PROVIDER: S-EPMC11957112 | biostudies-literature | 2025 Mar

REPOSITORIES: biostudies-literature