General expressions for R_1ρ relaxation for N-site chemical exchange and the special case of linear chains.

ABSTRACT: Exploration of dynamic processes in proteins and nucleic acids by spin-locking NMR experiments has been facilitated by the development of theoretical expressions for the R_1ρ relaxation rate constant covering a variety of kinetic situations. Herein, we present a generalized approximation to the chemical exchange, R_ex, component of R_1ρ for arbitrary kinetic schemes, assuming the presence of a dominant major site population, derived from the negative reciprocal trace of the inverse Bloch-McConnell evolution matrix. This approximation is equivalent to first-order truncation of the characteristic polynomial derived from the Bloch-McConnell evolution matrix. For three- and four-site chemical exchange, the first-order approximations are suffi

SUBMITTER: Koss H 

PROVIDER: S-EPMC5199238 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature