Structure and ligand binding of the ADP-binding domain of the NAD⁺ riboswitch.

ABSTRACT: The nadA motif is the first known NAD⁺-dependent riboswitch, comprising two similar tandem bulged stem-loop structures. We have determined the structure of the 5' domain 1 of the riboswitch. It has three coaxial helical segments, separated by an ACANCCCC bulge and by an internal loop, with a tertiary contact between them that includes two C:G base pairs. We have determined the structure with a number of ligands related to NADH, but in each case only the ADP moiety is observed. The adenosine adopts an anti conformation, forms multiple hydrogen bonds across the width of the sugar edge of the penultimate C:G base pair of the helix preceding the bulge, and the observed contacts have been confirmed by mutagenesis and calorimetry. Two divalent metal ions play a key struc

SUBMITTER: Huang L 

PROVIDER: S-EPMC7297122 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature