PDBsum entry 3aql

Transferase

PDB id: 3aql

Contents

Protein chains

388 a.a.

Ligands

GOL ×2

Metals

_MG ×2

References listed in PDB file

Key reference

• Title: Mechanism for the alteration of the substrate specificities of template-Independent RNA polymerases.
• Authors: Y.Toh, D.Takeshita, T.Nagaike, T.Numata, K.Tomita.
• Ref.: Structure, 2011, 19, 232-243.
• PubMed id: 21300291

Abstract

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.