Kinetics of base-pair displacement in double-helical nucleic acids.

摘要

Processes that involve gaining access to buried bases within double-helical nucleic acids, such as base methylation by methyltransferases, involve capture of bases transiently displaced from the native double-helical structure. Methyltransferase catalysis is extremely slow for an enzyme catalyzed reaction. The rate-limiting step in methyltransferase catalysis is unknown. In order to determine whether base-flipping occurs in double-helical nucleic acids in the absence of methyltransferases, host-guest compounds are used to capture the flipped out intermediate. ;Nucleic acid structural breathing is a dynamic event that has been characterized as having rate constants on the order of 10