A variety of spectroscopic techniques combined with density functional calculations are used to describe the electronic structure of the nonaxially ligated, trigonal planar type I copper site in three fungal laccases with substantially different type 1 copper reduction potentials. These methods are also applied to a mutant of the high-potential Polyporus pinsitis laccase in which the nonligating axial phenylalanine (Phe) is changed to methionine (Met). Optical absorption, circular dichroism, and magnetic circular dichroism spectroscopies of all three fungal laccases reveal that, relative to the classic blue copper protein plastocyanin, the ligand field strength at the type 1 Cu center and the oscillator strength of the charge-transfer transitions increase. Resonance Raman spectra show that the envelope of Cu-S(Cys) stretching bands is shifted to higher energy in the fungal laccases, implying a stronger Cu-S(Cys) bond. Differences in the EPR spectra of the fungal laccases and plastocyanin are found to result from the increased ligand field and decreased 4s mixing into the Cu d(x2-y2) half-tilled, highest occupied molecular orbital (HOMO). All three fungal laccases display similar spectroscopic properties despite their differing reduction potentials. Electronic absorption, circular dichroism (CD), magnetic circular dichroism (MCD), resonance Raman, and EPR spectroscopies show significant perturbation of the electronic structure of the fungal laccase type 1 copper site upon mutation of the axial Phe to Met, consistent with the site becoming more like that in plastocyanin, which has an axial Met ligand; the ligand field decreases, covalency of the Cu-S(Cys) bond decreases, and the Raman shifts of the Cu-S stretching bands decrease. Density functional calculations on the fungal laccase site provide insight into the origin of the experimentally observed increase in covalency and ligand field strength. These calculations show that it is the elimination of the Met ligand donor interaction that leads to an increase in the donor strength of the S(Cys). The contribution of the axial ligand to the reduction potential is discussed.