AsclepioHemoglobin in 3D
A protein made of four chains (two α and two β), each with a heme group that has an iron atom at its center. Each iron binds one O₂ molecule: four per…
Explained for every age
For kids (7–11)
Hemoglobin is the red protein inside red blood cells. It is like a taxi with four seats: in the lungs, one oxygen molecule climbs into each seat, and it gets off wherever it is needed. This is its real shape, atom by atom.
For teens (12–16)
A protein made of four chains (two α and two β), each with a heme group that has an iron atom at its center. Each iron binds one O₂ molecule: four per hemoglobin, and 270 million hemoglobins per red blood cell. When the first O₂ binds, the protein changes shape and the others bind more easily (cooperativity). What you see is the real structure measured by X-ray crystallography (PDB 1A3N).
Pre-Med (17+)
α₂β₂ tetramer (141 and 146 amino acids; 64.5 kDa) with one heme (protoporphyrin IX-Fe²⁺) per subunit; Fe is coordinated by the proximal histidine F8 and O₂ binds on the distal side (histidine E7). T (deoxy, low affinity) → R (oxy) transition: sigmoidal curve, P50 ≈ 27 mmHg. Bohr effect (H⁺ and CO₂ shift it to the right), 2,3-BPG, temperature. HbF (γ instead of β) has higher affinity. Structure 1A3N: human deoxyhemoglobin at 1.8 Å (Tame and Vallone, 2000).
What you can explore
Alpha globin chainBeta globin chainHeme groupOxygen binding site
Missions
- The oxygen taxi Explorer
- Four seats that tip each other off Discoverer
- Structure and dissociation curve Pre-Med