Unusual Dynamics and pKa Shift at the Active Site of a Lead-Dependent Ribozyme

摘要

Heteronuclear NMR spectroscopy has been used to probe the structure and dynamics of a lead-dependent ribozyme known as the leadzyme. The pKa's for all adenine bases in the leadzyme were measured and vary from <3.1 to 6.5. The adenines with the lowest pKa's are involved in Watson-Crick base pairs, and the adenine with the highest pKa is thought to form an AH~+ -C wobble base pair at the active site of the leadzyme.