Figure 6.

Mutations altering dimerization of Arnt and AhR PAS.A domains define a putative dimerization interface. (a) Residues found to be important for Arnt and AhR dimerization are illustrated on homology models of Arnt and AhR PAS.A domain. The mutations are coloured according to the severity of the defect in the lacZ reporter assay. For Arnt red: <60%, magenta: 61–70%, blue: 71–80% and green: >80% of wt activity (Figure 2a) and for AhR red: <60%, magenta: 61–80%, green: >80% of wt activity (Figure 5a). (b) Superimposition of PAS.A models of Arnt and AhR onto the structure 3F1P of HIF-2α/Arnt PAS.B (49) suggests dimerization occurs through different interfaces for PAS A and PAS B domains.