MolView

A Molstar-based protein viewer for Jupyter notebooks with a py3dmol-compatible API.

Features

• py3dmol-compatible API - Easy transition from py3dmol
• Powered by Molstar - Advanced molecular visualization engine
• Rich color themes - 7 color modes including rainbow gradients and pLDDT confidence
• Surface rendering - Customizable molecular surfaces
• Illustrative style - Artistic rendering with outlines
• Direct PDB/AlphaFold fetching - Download structures without leaving Python
• Grid layout - Compare multiple structures side-by-side
• Jupyter integration - Native display in notebooks

Installation

pip install -e .

Quick Start

import molview as mv

# Create viewer
v = mv.view(width=800, height=600)

# Load structure
with open('protein.pdb') as f:
    v.addModel(f.read(), 'pdb')

# Display
v.show()

Fetching Structures from Databases

MolView can directly fetch structures from RCSB PDB and AlphaFold DB:

Fetch from RCSB PDB

import molview as mv

# Fetch ubiquitin structure (1UBQ)
data = mv.fetch_pdb('1UBQ')

v = mv.view()
v.addModel(data, 'pdb')
v.show()

Fetch mmCIF format

# Fetch in mmCIF format
data = mv.fetch_pdb('7BV2', format='mmcif')
v = mv.view()
v.addModel(data, 'mmcif')
v.show()

Fetch from AlphaFold DB

# Fetch AlphaFold prediction for Human ABL1 kinase
data = mv.fetch_alphafold('P00519')

v = mv.view()
v.addModel(data, 'mmcif')
v.setColorMode('plddt')  # Color by confidence
v.show()

Search PDB Database

# Search for structures
pdb_ids = mv.search_pdb('hemoglobin', max_results=5)
print(pdb_ids)  # ['1A3N', '1GZX', '2HHB', ...]

# Visualize first result
if pdb_ids:
    data = mv.fetch_pdb(pdb_ids[0])
    v = mv.view()
    v.addModel(data, 'pdb')
    v.show()

Color Modes

MolView supports all color modes from the nano protein viewer:

1. Element (by atom type)

v.setColorMode('element')

2. Custom (single color)

v.setColorMode('custom', color='#FF0000')  # Red
v.setColorMode('custom', color='#4ECDC4')  # Teal (default)

3. Residue (by amino acid)

v.setColorMode('residue')

4. Chain (by chain ID)

# Auto colors
v.setColorMode('chain')

# Custom chain colors
v.setColorMode('chain', custom_colors={
    'A': '#FF0000',  # Red
    'B': '#00FF00',  # Green
    'C': '#0000FF'   # Blue
})

5. Secondary Structure

# Default colors (helix=blue, sheet=green, coil=gray)
v.setColorMode('secondary')

# Custom colors
v.setColorMode('secondary',
    helix_color='#FF0000',  # Red helices
    sheet_color='#00FF00',  # Green sheets
    coil_color='#0000FF'    # Blue coils
)

6. Rainbow (gradient by sequence)

# Available palettes: 'rainbow', 'viridis', 'plasma', 'magma', 'blue-red', 'pastel'
v.setColorMode('rainbow', palette='viridis')
v.setColorMode('rainbow', palette='plasma')
v.setColorMode('rainbow', palette='magma')

7. pLDDT (confidence for predicted structures)

v.setColorMode('plddt')

Grid Viewer (Multiple Structures)

Compare multiple structures side-by-side in a grid layout:

# Create a 2x2 grid
v = mv.view(viewergrid=(2, 2), width=900, height=900)

# Load structures into specific positions
v.addModel(pdb1, 'pdb', viewer=(0, 0))  # Top-left
v.addModel(pdb2, 'pdb', viewer=(0, 1))  # Top-right
v.addModel(pdb3, 'pdb', viewer=(1, 0))  # Bottom-left
v.addModel(pdb4, 'pdb', viewer=(1, 1))  # Bottom-right

# Settings apply to all viewers
v.setColorMode('rainbow', palette='viridis')
v.setSurface(True, opacity=40)
v.show()

Note: In grid mode, the viewer=(row, col) parameter is required for addModel().

See example/grid_examples.ipynb for more grid layout examples.

Advanced Features

Surface Rendering

# Enable surface with default opacity (40%)
v.setSurface(True)

# Custom opacity (0-100)
v.setSurface(True, opacity=60)

# Custom surface color
v.setSurface(True, opacity=40, inherit_color=False, color='#FF0000')

Illustrative Style

# Enable artistic rendering with outlines
v.setIllustrativeStyle(True)

Camera Controls

# Reset camera view
v.zoomTo()

# Enable continuous rotation
v.spin(True)

Background Color

v.setBackgroundColor('#000000')  # Black
v.setBackgroundColor('#FFFFFF')  # White

Complete Example

import molview as mv

# Create viewer
v = mv.view(width=800, height=600)

# Load structure
with open('protein.pdb') as f:
    pdb_data = f.read()
v.addModel(pdb_data, 'pdb')

# Set rainbow coloring with viridis palette
v.setColorMode('rainbow', palette='viridis')

# Add semi-transparent surface
v.setSurface(True, opacity=40)

# Enable illustrative style
v.setIllustrativeStyle(True)

# Set black background
v.setBackgroundColor('#000000')

# Display
v.show()

Comparison with py3dmol

MolView is designed to be a drop-in replacement for py3dmol with additional features:

py3dmol code:

import py3dmol
v = py3dmol.view(width=800, height=600)
v.addModel(pdb_data, 'pdb')
v.setStyle({'cartoon': {'color': 'spectrum'}})
v.show()

Equivalent MolView code:

import molview as mv
v = mv.view(width=800, height=600)
v.addModel(pdb_data, 'pdb')
v.setColorMode('rainbow')
v.show()

Supported Formats

• PDB - Protein Data Bank format
• mmCIF - Macromolecular Crystallographic Information File
• SDF - Structure Data File (coming soon)

API Reference

Viewer Creation

• view(width, height, viewergrid) - Create viewer instance
  • viewergrid=(rows, cols) - Optional grid layout for multiple structures

Model Management

• addModel(data, format, viewer) - Load structure data
  • viewer=(row, col) - Required in grid mode to specify position
• clear() - Remove all models

Fetching Structures

• fetch_pdb(pdb_id, format='pdb') - Fetch structure from RCSB PDB
• query(pdb_id, format='pdb') - Alias for fetch_pdb (py3dmol compatibility)
• fetch_alphafold(uniprot_id, version=4) - Fetch AlphaFold prediction
• search_pdb(query_text, max_results=10) - Search PDB database

Styling

• setColorMode(mode, **kwargs) - Set color theme
• setStyle(style) - Set representation (cartoon default)
• setSurface(enabled, opacity, inherit_color, color) - Configure surface
• setIllustrativeStyle(enabled) - Toggle illustrative rendering
• setBackgroundColor(color) - Set background

Camera

• zoomTo() - Reset camera view
• spin(enabled) - Toggle continuous rotation

Display

• show() - Render in notebook

Color Palettes

Rainbow Palettes

Available palettes for setColorMode('rainbow', palette='...'):

• 'rainbow' - Classic rainbow (ROYGBIV)
• 'viridis' - Perceptually uniform (purple to yellow)
• 'plasma' - Bright and vibrant (purple to yellow)
• 'magma' - Dark and moody (black to white)
• 'blue-red' - Simple blue to red gradient
• 'pastel' - Soft pastel colors

Custom Color Palette

Pre-defined colors for setColorMode('custom', color='...'):

• Teal: #4ECDC4 (default)
• Red: #FF6B6B
• Blue: #4DABF7
• Green: #69DB7C
• Yellow: #FFD93D
• Orange: #FF922B
• Purple: #DA77F2
• Pink: #FF8CC8
• Cyan: #15AABF
• Gray: #868E96

Requirements

• Python >=3.7
• IPython >=7.0.0
• Jupyter >=1.0.0

License

MIT License

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Repository: github.com/54yyyu/molview

This package uses modern Python packaging with pyproject.toml (PEP 517/518).

Acknowledgments

• Built with Molstar - Modern molecular visualization toolkit
• API inspired by py3dmol - Python interface to 3Dmol.js
• Color palettes from scientific visualization best practices

Roadmap

• Multiple viewer grid support
• Selection and highlighting
• Animation playback
• Label/annotation support
• Export to image/video
• Additional representation styles (stick, sphere, line)
• Measurement tools
• Surface customization options