3D Printing: Serum Albumin

PDB structure used to generate the model file: 1e7i

Model generated with: Molecular Maya/Autodesk Maya

Model physical size (in mm): 90 x 52 x 90

Printed on: Ultimaker S3. The image on the left shows the support system generated by the printer in the printer interface. The image on the right shows the printed model with support system removed. We recommend keeping the model in the water bath for a couple of days to fully dissolve the support material inside the hydrophobic tunnels.

Model material: PLA

Support material: PVA (water soluble)

Output scale: 100%

Image 1

Image 2

Image 3

Serum albumin is a carrier protein. It transports fatty acids and other substances in the blood. The protein has multiple hydrophobic tunnels to accommodate the hydrophobic parts of the molecules it transports.

The PDB structure 1e7i has 7 molecules of stearic acid in different sites. When creating the model, the ligands were removed, and hollow tunnels were modeled at the ligand interaction sites. The tunnels can accommodate insertable small parts that will represent the small molecules. The model was hand-painted in bright green for easier visual locating of the tunnels. The stearic acid molecules were modeled using pipe cleaners. In addition, the hydrophilic ‘head’ for each ligand was indicated by gluing a 5mm melty bead onto the pipe cleaner (Image 1).

The stearic acids molecules interact with the protein in distinct orientations. One way to make sure the stearic acid models are inserted correctly into the model is to hand-paint landmarks on the model at the sites of hydrophilic interaction, another way is to explore the ligand orientations along with a 3D Molecular viewer such as Mol* (introductory video tutorial is available)  available from the 1e7i Structure Summary page (Image 2).

The models of small molecules can be inserted into the 3D printed protein to demonstrate the protein shape-function relationship (Image 3).