Binding constant of riboswitch to TPP (thiamine pyrophosphate)

Range 210 aptamer 1 alone: 850 aptamer 2 alone pM
Organism Bacteria Bacillus anthracis
Reference Welz R, Breaker RR. 2007. Ligand binding and gene control characteristics of tandem riboswitches in Bacillus anthracis. RNA 13: 573–582. p.575 right column 3rd paragraphPubMed ID17307816
Comments "The levels of spontaneous cleavage at three positions (site 1, A44 site 2, U91 site 3, A104) were quantitated and used to estimate the apparent dissociation constant (KD) for ligand binding (Fig. 4B). The KD value determined for aptamer 1 alone (210 pM) is >10-fold better than the values measured for other tight-binding riboswitch aptamers (e.g., Winkler et al. 2002a, 2003 Mandal et al. 2003). Similarly, the KD value for TPP binding by aptamer 2 (850 pM Fig. 4C) also represents one of the tightest aptamer–metabolite interactions measured to date. These findings support [researchers'] prediction that both B. anthracis tenA aptamers sense TPP."
Entered by Uri M
ID 110863