Crystal structure of an in vitro evolved tetracycline aptamer and artificial riboswitch
[SNRPA_HUMAN] Binds stem loop II of U1 snRNA. It is the first snRNP to interact with pre-mRNA. This interaction is required for the subsequent binding of U2 snRNP and the U4/U6/U5 tri-snRNP. In a snRNP-free form (SF-A) may be involved in coupled pre-mRNA splicing and polyadenylation process. Binds preferentially to the 5'-UGCAC-3' motif in vitro.
Publication Abstract from PubMed
The tetracycline aptamer is an in vitro selected RNA that binds to the antibiotic with the highest known affinity of an artificial RNA for a small molecule (Kd approximately 0.8 nM). It is one of few aptamers known to be capable of modulating gene expression in vivo. The 2.2 A resolution cocrystal structure of the aptamer reveals a pseudoknot-like fold formed by tertiary interactions between an 11 nucleotide loop and the minor groove of an irregular helix. Tetracycline binds within this interface as a magnesium ion chelate. The structure, together with previous biochemical and biophysical data, indicates that the aptamer undergoes localized folding concomitant with tetracycline binding. The three-helix junction, h-shaped architecture of this artificial RNA is more complex than those of most aptamers and is reminiscent of the structures of some natural riboswitches.
Structural basis for specific, high-affinity tetracycline binding by an in vitro evolved aptamer and artificial riboswitch.,Xiao H, Edwards TE, Ferre-D'Amare AR Chem Biol. 2008 Oct 20;15(10):1125-37. PMID:18940672
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.