A ribbon (cartoon) model of bovine pancreatic trypsin inhibitor (BPTI, also known as aprotinin), based on PDB entry 1PIT, a high-quality NMR solution structure. BPTI is a small, classic model protein of 58 amino acids, widely used in protein folding and structural biology education. Suitable for science education, scientific presentation slides, and scientific illustration and visualization.

--- Model Overview ---

• Source structure: PDB ID 1PIT (NMR solution structure of bovine pancreatic trypsin inhibitor)
• Method of source structure: Solution NMR (one conformer from the deposited NMR ensemble)
• Representation: Ribbon (cartoon) model
• Created in: Blender 5.2.2 LTS
• Vertex count: 7,808 (lightweight mesh)

--- Shading Options (.blend) ---The native .blend file includes switchable shading setups:

1. Rainbow gradient from N-terminus to C-terminus
2. Coloring by secondary structure
3. Coloring by chain (single color, see note below)
4. Coloring by B-factor (see note below)

--- UV Maps ---Three UV maps are included, encoding:

1. Relative position along the chain (N- to C-terminus) and secondary structure type
2. Chain identity
3. B-factor

These UV maps can be used to build your own custom materials and color schemes in other software.

Note on chain coloring: 1PIT contains a single polypeptide chain. The chain UV map and chain color scheme are included for consistency with our other protein models, but the chain coloring appears as a single color.

Note on B-factor coloring: The B-factor values are taken directly from the deposited PDB entry. Because this structure was determined by NMR spectroscopy rather than X-ray crystallography, the B-factor field does not represent crystallographic thermal motion and has no standard physical meaning in NMR entries. The B-factor coloring is included for consistency with our other protein models and should not be interpreted as a measure of flexibility or structural quality.

--- File Formats ---

• .blend: Full scene with all four shading options and three UV maps.
• .fbx: Includes the three UV maps and color data for the secondary-structure and chain color schemes. The N-to-C gradient and B-factor shading are not included.
• .obj: Includes the three UV maps and color data for the secondary-structure and chain color schemes. The N-to-C gradient and B-factor shading are not included.
• .stl: Geometry only (no UV or material data).

Note: The FBX, OBJ, and STL files were generated using Blender's built-in exporters and have not been tested in other software. Appearance may vary depending on the importing application.

--- Disclaimer ---This model is intended for visualization and educational purposes. Its scientific accuracy is not guaranteed, and it should not be used as a reference for research or structural analysis.