  We introduce a stochastic sandwich method with low-mode substitution to
evaluate the connected three-point functions. The isovector matrix elements of
the nucleon for the axial-vector coupling $g_A^3$, scalar couplings $g_S^3$ and
the quark momentum fraction $\langle x\rangle_{u -d}$ are calculated with
overlap fermion on 2+1 flavor domain-wall configurations on a $24^3 \times 64$
lattice at $m_{\pi} = 330$ MeV with lattice spacing $a = 0.114$ fm.
