The development of novel antifungals capable of eliminating Aspergillus fungal infections and improving patient outcomes in Aspergillosis is essential. This work has focussed on Uric Acid Permease, a nucleobase-ascorbate transporter from Aspergillus nidulans, as a potential antifungal carrier. The existing crystal structure of UapA-G411VΔ1-11 in complex with xanthine (PDB 5I6C)1, has provided invaluable information about the substrate binding site, and allowed for the structure-guided design of derivatised xanthine analogues. Competitive uptake assays were used to obtain the binding affinity of each of the analogues for UapA in Aspergillus nidulans. 3-benzylxanthine (5) was identified as a novel ligand of UapA, binding with 35x higher affinity (KI = 0.2 μM) than the native substrates xanthine (KM = 7 μM) and uric acid (KI = 7 μM). This work describes the functional characterisation of 3-benzylxanthine (5) using fungal growth assays, and fluorescence microscopy. The effect of this substrate on UapA-WT and the thermostabilised mutants UapA-G411VΔ1-11 and UapA-Q408EΔ1-11 was assessed using cellular thermal shift assays (CETSA), fluorescence size-exclusion chromatography (FSEC), CPM-based thermostability assays and nano-differential scanning fluorimetry (nano-DSF). While these approaches had their challenges, they all demonstrated that 3-benzylxanthine (5) did not significantly destabilise UapA-WT or the thermostabilised mutants UapA-G411VΔ1-11 and UapA-Q408EΔ1-11. The later part of this work describes attempts to structurally characterize the binding interaction between 3-benzylxanthine (5) and UapA using X-ray crystallography, hydrogen-deuterium mass spectrometry (HDX-MS) and cryo-electron microscopy (cryo-EM). While the structure of UapA-WT or its mutants with 3-benzylxanthine (5) has not yet been resolved, preliminary results from hydrogen-deuterium mass spectrometry (HDX-MS) suggest that 3-benzylxanthine (5) may bind an outward or occluded conformation of UapA-Q408EΔ1-11. Structural characterisation of UapA with 3-benzylxanthine (5) using cryo-EM is ongoing. Once resolved, this will form the basis of future structure-guided xanthine analogue design initiatives.