Based on the density functional theory and using the full-potential linearized augmented-plane-waves method the electronic structure of PrBa2Cu3O7 (Pr123) system was calculated. The rotationally invariant local spin density approximation plus Hubbard parameter U was employed for Pr(4f) orbitals. One self-consistent solution more stable than the previous solution, which has been proposed by Liechtenstein and Mazin (LM), was found. In contrast to the LM solution, it can explain the results of the 17O NMR spectroscopy study of nonsuperconducting Pr123 samples. This new solution favors the suggestion that the pure Pr123 samples should be intrinsically superconductor and metal similar to the other RBa2Cu3O7 (R=Y or a rare earth element) samples. The imperfections cause the superconducting holes are transferred to the nonsuperconducting hole states around the high-symmetry (π/a, π/b, kz) line in the Brillouin zone and so, superconductivity is suppressed in the conventional samples. It predicts that the superconducting 2p < sub>σ holes in the O2 sites of nonsuperconducting Pr123 samples should be depleted and the ones in the O3 sites should be almost unchanged .