Glucokinase (GK) is an important enzyme for regulating blood
glucose levels and a potentially attractive target for diabetes of the
young type 2 and persistent hyperinsulinemic hypoglycemia of
infancy. To characterize the conformational transition of GK from
the closed state to the superopen state, a series of conventional
molecular dynamics (MD) and target MD (TMD) simulations were
performed on both the wild-type enzyme and its mutants. Two
10-ns conventional MD simulations showed that, although the
allosteric site of GK is20 ? away from the active site, the activator
is able to enhance the activity of the enzyme through conformational
restriction. Fourteen TMD simulations on GK and five of its
mutants revealed a reliably conformational transition pathway.
The overall conformational transition includes three stages, and
three likely stable intermediate states were identified by free
energy scanning for the snapshots throughout the pathway. The
conformational transition feature revealed by ourTMDsimulations
rationalized several important mutagenesis and kinetic data. Remarkably,
the TMD simulations predicted that Y61S, I159A, A201R,
V203E, and V452S mutations, which have not been investigated so
far, may facilitate the opening process of GK. These predictions
also have been verified by mutagenesis and kinetic analyses in this
study. These observations are beneficial to understanding the
mechanism of GK regulation and designing the compounds for
treating metabolic diseases.