Erratum: 'conformational heterogeneity of the SAM-I riboswitch transcriptional on state: A chaperone-like role for S-adenosyl methionine (Journal of Molecular Biology (2012) 418 (331-349))

摘要

The authors regret that there is a mistake in the legend to Fig. 3. The corrected legend appears below. Fig. 3. Extension of the metF SAM-I riboswitch RNA transcripts to include ATI is required to observe SAM-induced strand switching by NMR. The ID imino proton spectrum is shown at 35 °C under three different conditions—no Mg~(2+), in the presence of 2 mM Mg , and with Mg~(2+) and 5:1 ratio [SAM]/[RNA]. (a) SAM-I riboswitch RNA construct containing "strand switching" elements capable of forming the PI or the ATI helix (similar to the ATI helix but with two U residues truncated), (b) Truncated aptamer sequence capable of forming only Pl-helix-containing conformers. (c) Construct truncated at the 5' end to prevent PI helix conformation, (d) Isolated ATI helix construct. For the ATI-containing RNA shown in (a), addition of SAM reduces the intensity of a signal associated with GU base pair within ATI helix (yellow), while increasing the intensity of another signal previously observed in truncated aptamer (pink). Note that whereas constructs used in (a) and (b) contain wild-type sequences, RNAs used in (c) and (d) contain a UUCG tetraloop substitution in the AT helix, giving rise to a signal at 9.7 ppm. Also, please note that the boxed spectra on the bottom two panels are duplicates of the spectra with SAM absent.