Structural analysis
There is no crystal structure of the protein carrying described deletion; however, the analysis of the native conformation of the molybdopterin synthase and comparison with the structure fromStaphylococcus aureus complexed with precursor Z shed light on the consequences of the deletion. Human molybdopterin synthase complex was crystallized as a dimer constituted of two heterodimers. Each heterodimer consists of molybdopterin synthase sulfur carrier subunit and molybdopterin synthase catalytic subunit. The Leu158 and Lys159 deletion occur in the catalytic subunit. The Leu158 and Lys159 residues are located at the end of the last helix, close to the C-terminus of the subunit, and together with the C-terminus, they participate in the molybdopterin synthase sulfur carrier subunit binding (Figure 2A). Moreover, the comparison of the structures of molybdopterin synthases from human and Staphylococcus aureus suggests, that the Lys159 residue is essential for precursor Z binding (Figure 2B).
Figure 2