Full-Length NAD⁺-I Riboswitches Bind a Single Cofactor but Cannot Discriminate against Adenosine Triphosphate.

ABSTRACT: Bacterial riboswitches are structured RNAs that bind small metabolites to control downstream gene expression. Two riboswitch classes have been reported to sense nicotinamide adenine dinucleotide (NAD⁺), which plays a key redox role in cellular metabolism. The NAD⁺-I (class I) riboswitch stands out because it comprises two homologous, tandemly arranged domains. However, previous studies examined the isolated domains rather than the full-length riboswitch. Crystallography and ligand binding analyses led to the hypothesis that each domain senses NAD⁺ but with disparate equilibrium binding constants (K_D) of 127 μM (domain I) and 3.4 mM (domain II). Here, we analyzed individual domains and the full-length riboswitch by isothermal titration calo

SUBMITTER: Srivastava Y 

PROVIDER: S-EPMC10702441 | biostudies-literature | 2023 Dec

REPOSITORIES: biostudies-literature