We report the LDA+Uf calculations of the electronic structure of ABa2Cu3O7, (A=Pr, Nd). For A=Pr an additional band crosses the Fermi level, grabbing holes from the (super)conducting CuO2 band. For A=Nd this band remains completely filled, thus explaining the absence of Tc suppression. On doping LnBa2Cu3O7 with Pr the position of the hole-depleting band depends crucially of the atomic number of the host rare earth, through the position of its f-band. This makes Tc supression in doped compounds different for different hosts, the stronger the smaller the atomic number of the host is.
 

Physica C, 235-240 2121-2, 1994.