  In the presence of ATP, kinesin proceeds along the protofilament of
microtubule by alternated binding of two motor domains on the tubulin binding
sites. Since the processivity of kinesin is much higher than other motor
proteins, it has been speculated that there exists a mechanism for allosteric
regulation between the two monomers. Recent experiments suggest that ATP
binding to the leading head domain in kinesin is regulated by the rearward
strain built on the neck-linker. We test this hypothesis by explicitly modeling
a $C_{\alpha}$-based kinesin structure whose both motor domains are bound on
the tubulin binding sites. The equilibrium structures of kinesin on the
microtubule show disordered and ordered neck-linker configurations for the
leading and the trailing head, respectively. The comparison of the structures
between the two heads shows that several native contacts present at the
nucleotide binding site in the leading head are less intact than those in the
binding site of the rear head. The network of native contacts obtained from
this comparison provides the internal tension propagation pathway, which leads
to the disruption of the nucleotide binding site in the leading head. Also,
using an argument based on polymer theory, we estimate the internal tension
built on the neck-linker to be f~(12-15) pN. Both of these conclusions support
the experimental hypothesis.
