Jared Travnicek Medical & Scientific Illustration info@jtsciencevisuals.com

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Hemoglobin Transformation

This animation was created for an online module for the Scientific Foundations of Medicine course at the Johns Hopkins University School of Medicine. It was made in collaboration with Dr. Sandra Gabelli and Dr. Jon Lorch from the Department of Biophysics and Biophysical Chemistry at Johns Hopkins. The 3D models and animations were created in Cinema 4D and composited and further animated in After Effects.

The tertiary structures of the alpha and beta subunits are very similar to each other and to myoglobin, a protein that stores oxygen in the muscles. There are extensive interactions between the alpha 1 and beta 1 monomers and between the alpha 2 and beta 2 monomers that make up each dimer. The interface between the two dimers involves fewer interactions, but these interactions are critical to cooperativity and allostery. In the dimer-dimer interface, alpha subunits face alpha subunits and beta subunits face beta subunits across a channel about 20 angstroms wide.

Narration: Oxygenation causes a change in the quaternary structure, represented here by the color change from blue to red. The conformational change involves the interfaces between the dimers alpha 1 beta 2 and alpha 2 beta 1 without affecting the interactions between the subunits within each dimer. Oxygenation causes rotation of the alpha 1 beta 1 dimer by 15 degrees with respect to the alpha 2 beta 2 dimer. Some atoms at the interface between alpha 1 and beta 2 shift about 6 angstroms relative to each other. The deoxygenated form of hemoglobin is called the T state and the oxygenated form is called the R state.

In this 3D medical animation: Hemoglobin, Dimer, Monomer, Polypeptide chain, Heme, T state, R state, Quaternary structure, Oxygen, Molecule