Binding constant of riboswitch to cyclic dimeric-guanosine monophosphate (c-di-GMP)

Range ~10 Table - link pM
Organism Bacteria Vibrio cholerae
Reference Smith KD, Lipchock SV, Ames TD, Wang J, Breaker RR, Strobel SA. Structural basis of ligand binding by a c-di-GMP riboswitch. Nat Struct Mol Biol. 2009 Dec16(12):1218-23. doi: 10.1038/nsmb.1702. p.1220 right column top paragraph & p.1221 table 1PubMed ID19898477
Method "[Researchers] tested predictions resulting from the c-di-GMP riboswitch structure through the use of a gel-shift assay that makes it possible to directly measure the RNA–c-di-GMP interaction using radiolabeled c-di-GMP (Fig. 3a). [They] used this assay to measure the equilibrium dissociation constant (Kd) for the wild-type RNA construct 110 Vc2, originally measured as approximately 1 nM by in-line probing (BNID 110866)."
Comments "The ratio of koff and kon gives an estimate of the Kd for c-di-GMP binding to the aptamer of approximately 10 pM (Table 1). To [researchers'] knowledge, this is the tightest affinity measured for an RNA–small molecule interaction...The presence of even a single molecule of c-di-GMP in the cell corresponds to a concentration of approximately 1 nM (ref 1). If [researchers] assume that in vitro measurements approximate what occurs in the cell, this is approximately 100-fold above the 10 pM Kd for the riboswitch– c-di-GMP interaction." See notes beneath table
Entered by Uri M
ID 110867