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== Publication Abstract from PubMed ==

PolyA polymerase (PAP) adds a polyA tail onto the 3'-end of RNAs without a nucleic acid template, using adenosine-5'-triphosphate (ATP) as a substrate. The mechanism for the substrate selection by eubacterial PAP remains obscure. Structural and biochemical studies of Escherichia coli PAP (EcPAP) revealed that the shape and size of the nucleobase-interacting pocket of EcPAP are maintained by an intra-molecular hydrogen-network, making it suitable for the accommodation of only ATP, using a single amino acid, Arg(197). The pocket structure is sustained by interactions between the catalytic domain and the RNA-binding domain. EcPAP has a flexible basic C-terminal region that contributes to optimal RNA translocation for processive adenosine 5'-monophosphate (AMP) incorporations onto the 3'-end of RNAs. A comparison of the EcPAP structure with those of other template-independent RNA polymerases suggests that structural changes of domain(s) outside the conserved catalytic core domain altered the substrate specificities of the template-independent RNA polymerases.

Mechanism for the alteration of the substrate specificities of template-independent RNA polymerases.,Toh Y, Takeshita D, Nagaike T, Numata T, Tomita K Structure. 2011 Feb 9;19(2):232-43. PMID:21300291<ref>PMID:21300291</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

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