NMR solution structures of Runella slithyformis RNA 2'-phosphotransferase Tpt1 provide insights into NAD+ binding and specificity.

ABSTRACT: Tpt1, an essential component of the fungal and plant tRNA splicing machinery, catalyzes transfer of an internal RNA 2'-PO4 to NAD+ yielding RNA 2'-OH and ADP-ribose-1',2'-cyclic phosphate products. Here, we report NMR structures of the Tpt1 ortholog from the bacterium Runella slithyformis (RslTpt1), as apoenzyme and bound to NAD+. RslTpt1 consists of N- and C-terminal lobes with substantial inter-lobe dynamics in the free and NAD+-bound states. ITC measurements of RslTpt1 binding to NAD+ (KD ∼31 μM), ADP-ribose (∼96 μM) and ADP (∼123 μM) indicate that substrate affinity is determined primarily by the ADP moiety; no binding of NMN or nicotinamide is observed by ITC. NAD+-induced chemical shift perturbations (CSPs) localize exclusively to the RslTpt1 C-lobe. NADP+, which contains an adenylat

SUBMITTER: Alphonse S 

PROVIDER: S-EPMC8464070 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature