5y85

Publication Abstract from PubMed

Here we report on the crystal structure and cleavage assays of a four-way junctional twister-sister self-cleaving ribozyme. Notably, 11 conserved spatially separated loop nucleotides are brought into close proximity at the ribozyme core through long-range interactions mediated by hydrated Mg2+ cations. The C62-A63 step at the cleavage site adopts a splayed-apart orientation, with flexible C62 directed outwards, whereas A63 is directed inwards and anchored by stacking and hydrogen-bonding interactions. Structure-guided studies of key base, sugar, and phosphate mutations in the twister-sister ribozyme, suggest contributions to the cleavage chemistry from interactions between a guanine at the active site and the non-bridging oxygen of the scissile phosphate, a feature found previously also for the related twister ribozyme. Our four-way junctional pre-catalytic structure differs significantly in the alignment at the cleavage step (splayed-apart vs. base-stacked) and surrounding residues and hydrated Mg2+ ions relative to a reported three-way junctional pre-catalytic structure of the twister-sister ribozyme.

Structure-based insights into self-cleavage by a four-way junctional twister-sister ribozyme.,Zheng L, Mairhofer E, Teplova M, Zhang Y, Ma J, Patel DJ, Micura R, Ren A Nat Commun. 2017 Oct 30;8(1):1180. doi: 10.1038/s41467-017-01276-y. PMID:29081514^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.