Template-dependent 3'-5' nucleotide addition is a shared feature of tRNA^sup His^ guanylyltransferase enzymes from multiple domains of life

The presence of an additional 5' guanosine residue (...) is a unique feature of ... ... is incorporated posttranscriptionally in eukarya via an unusual 3' - 5' nucleotide addition reaction catalyzed by the ... guanylyltransferase (Thg1). Yeast Thg1 catalyzes an unexpected second activ...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2010-01, Vol.107 (2), p.674
Main Authors: Abad, Maria G, Rao, Bhalchandra S, Jaekman, Jane E
Format: Article
Language:English
Subjects:
DNA polymerase
Enzyme kinetics
Enzymes
Ribonucleic acid
RNA
Transfer RNA
Yeast
Online Access:Get full text
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Summary:The presence of an additional 5' guanosine residue (...) is a unique feature of ... ... is incorporated posttranscriptionally in eukarya via an unusual 3' - 5' nucleotide addition reaction catalyzed by the ... guanylyltransferase (Thg1). Yeast Thg1 catalyzes an unexpected second activity: Watson - Crick-dependent 3' - 5' nucleotide addition that occurs in the opposite direction to nucleotide addition by all known DNA and RNA polymerases. This discovery led to the hypothesis that there are alternative roles for Thg1 family members that take advantage of this unusual enzymatic activity. Here we show that archaeal homologs of Thg1 catalyze ... addition, in vitro and in vivo in yeast, but only in a templated reaction, i.e. with ... substrates that contain a ... discriminator nucleotide. Because ... from archaea contains ..., these findings are consistent with a physiological function for templated nucleotide addition in archaeal ... maturation. Moreover, unlike yeast Thg1, archaeal Thg1 enzymes also exhibit a preference for template-dependent ... addition to ...-containing ... . Taken together, these results demonstrate that Watson - Crick template-dependent 3' - 5' nucleotide addition is a shared catalytic activity exhibited by Thg1 family members from multiple domains of life, and therefore, that this unusual reaction may constitute an ancestral activity present in the earliest members of the Thg1 enzyme family. (ProQuest: ... denotes formulae/symbols omitted.)
ISSN:0027-8424
1091-6490