Mutations in the basic loop of the Zn binuclear cluster of the UaY transcriptional activator suppress mutations in the dimerisation domain

► UaY is the transcriptional regulator of purine utilisation in Aspergillus nidulans. ► The uaY109 mutation maps in the dimerization element of the Zn2/6Cys domain. ► UaY109 affects differentially gene expression and promoter binding. ► Suppressors map in the first loop of the Zn2/6Cys domain. ► Molecular models of the Zn2/6Cys-DNA wild type and mutant complexes are presented.