  We have performed an angle-resolved photoemission study on untwinned
PrBa$_2$Cu$_3$O$_7$, which has low resistivity but does not show
superconductivity. We have observed a dispersive feature with a band maximum
around ($\pi$/2,$\pi$/2), indicating that this band is derived from the undoped
CuO$_2$ plane. We have observed another dispersive band exhibiting
one-dimensional character, which we attribute to signals from the doped CuO$_3$
chain. The overall band dispersion of the one-dimensional band agrees with the
prediction of $t-J$ model calculation with parameters relevant to cuprates
except that the intensity near the Fermi level is considerably suppressed in
the experiment.
