(a), (c) and (e) Structural models of GalP (based on GLUT5, PDB 4YBQ), Mhp1 (PDB 2JLN) and AAC (based on Aac2p, PDB 4C9G), respectively. The models are shown in rainbow cartoon and wheat surface representations. Cysteine residues are shown as spheres, except for Cys-19 of GalP, which could not be modeled. (b), (d) and (f) Thermostability screen of GalP (3 μg), Mhp1 (3 μg) and AAC (2 μg) against sugar (50 mM final concentration), nucleobase (2 mM) and nucleotide libraries (2.5 mM), respectively. The temperature shift (ΔTm) is the apparent melting temperature in the presence of compound minus the apparent melting temperature in the absence of compound. The data are represented by the standard deviation of five, three and three independent repeats, respectively. Two-tailed Student’s t-tests assuming unequal variances were performed for the significance analysis (0.05 < p-value: not significant; 0.01 < p-value<0.05: *; 0.001 < p-value<0.01: **; 0.0001 < p-value<0.001: ***; p-value<0.0001: ****). L-BH, 5-benzyl-L-hydantoin; BVH, 5-bromovinylhydantoin; L-IMH, 5-indolylmethyl-L-hydantoin, L-NMH 5- (2-naphthylmethyl)-L-hydantoin.