Locations of β17 domain HE/HPP mutations in the tetramer complex. Mutations that have been associated with HE or HPP are indicated as space-filling spheres on the ribbon diagram. Where known, the relationship to reported binding affinities⁵¹  are color coded by the use of binding affinity categories similar to those used in Gaetani et al¹⁷ : red = severe (marginal or no detected binding); orange = moderate (∼ 100-fold weaker than wild type); yellow = modest (∼ 10-fold weaker than wild type); green = no effect (wild-type binding); gray = not characterized. (A) Mutations that disrupt the local structure of the β17 domain. (B) Mutations predicted to disrupt the local structure of the β17 domain. (C) Mutations predicted to disrupt association of the β17 domain with the α0 domain.