Figure 1. Structure of Hbα.
(A) HbA is a heterotetramer with two a subunits (gray) and two β subunits (purple). (B) Monomeric Hbα (rendered in cartoon) is stabilized by AHSP (surface representation). The overall backbone fold of Hbα bound to AHSP (C and D, gray) is similar to Hbα (C, yellow) and Hbβ (D, orange) of HbA.