Use of Both Direct and Indirect ¹³C Tags for Probing Nitrogen Interactions in Hairpin Ribozyme Models by ¹⁵N NMR

Abstract

We have used the synthesis and ¹⁵N NMR study of separate loop A and loop B domains of the hairpin ribozyme to demonstrate that multiple ¹⁵N atoms can be incorporated into an RNA strand and be unambiguously distinguished through a combination of direct and indirect tagging by ¹³C atoms. Absence of ¹⁵N chemical shift changes shows that the G8N1 in loop A does not become deprotonated up to pH 8, and that the G21N7 of loop B does not bind to Mg^2 +.

^†In honor and celebration of the 70th birthday of Professor Leroy B. Townsend.

Keywords:

• Hairpin ribozyme
• ¹⁵N NMR
• ¹³C tag
• Specific labeling

Acknowledgments

We thank Seho Kim for assistance with the 2D NMR. This work was supported by grants from the National Institutes of Health (GM48802 and GM60485).

Notes

^†In honor and celebration of the 70th birthday of Professor Leroy B. Townsend.