Minimal and extended hammerheads utilize a similar dynamic reaction mechanism for catalysis. Journal Article uri icon



  • Analysis of the catalytic activity of identical mutations in the catalytic cores of nHH8, a very active "extended" hammerhead, and HH16, a less active "minimal" hammerhead, reveal that the tertiary Watson-Crick base pair between C3 and G8 seen in the recent structure of the Schistosoma mansoni extended hammerhead can be replaced by other base pairs in both backgrounds. This supports the model that both hammerheads utilize a similar catalytic mechanism but HH16 is slower because it infrequently samples the active conformation. The relative effect of different mutations at positions 3 and 8 also depends on the identity of residue 17 in both nHH8 and HH16. This synergistic effect can best be explained by transient pairing between residues 3 and 17 and 8 and 13, which stabilize an inactive conformation. Thus, mutants of nHH8 and possibly nHH8 itself are also in dynamic equilibrium with an inactive conformation that may resemble the X-ray structure of a minimal hammerhead. Therefore, both minimal and extended hammerhead structures must be considered to fully understand hammerhead catalysis.

publication date

  • January 1, 2008

has restriction

  • bronze

Date in CU Experts

  • March 13, 2015 12:56 PM

Full Author List

  • Nelson JA; Uhlenbeck OC

author count

  • 2

published in

  • RNA  Journal

Other Profiles

Electronic International Standard Serial Number (EISSN)

  • 1469-9001

Additional Document Info

start page

  • 43

end page

  • 54


  • 14


  • 1