Representations & Colors

Build a clear molecular scene by choosing how each component is drawn and colored.

A representation controls geometry: ribbon, atoms, bonds, points, or a surface. A color scheme controls meaning: element, chain, residue, secondary structure, sequence, hydrophobicity, or a uniform color. Set both per component so the visual hierarchy matches the scientific question.

The 1CBS protein displayed as a ribbon colored by secondary structure, with its ligand displayed as spacefill and the Display panel visible. — A readable protein–ligand overview: protein as **Cartoon / Ribbon** colored by secondary structure, ligand as **Spacefill (CPK)** colored by element, and water hidden.

Representation and color answer different questions

First choose how the component is drawn, then choose what its colors mean. Changing one does not automatically change the other.

Start with the question

Scientific question	Recommended representation	Recommended color
What is the overall protein fold?	Cartoon / Ribbon	Secondary Structure or Chain
Which atoms form a ligand contact?	Protein Ribbon with atom overlay; ligand Ball & Stick	Protein Uniform; ligand Element
How tightly is a ligand packed?	Protein Surface or Ribbon; ligand Spacefill (CPK)	Contrasting uniform protein and element-colored ligand
How do chains differ?	Cartoon / Ribbon	Chain
Where are hydrophobic regions?	Surface	Hydrophobicity
How does atomic volume fill a pocket?	Spacefill (CPK)	Element or Uniform
How can I keep a very large system responsive?	Line, Point, or Backbone where appropriate	A simple scheme such as Chain or Uniform

Change a component's representation

Activate the intended structure under Structures.

Open Display in the right sidebar.

Find the component, such as Protein, Ligand, Water, or Ion.

Choose the representation from that component's dropdown.

Rotate the scene and inspect the result from more than one angle.

The Protein style buttons provide fast global choices for the protein: Ribbon, Atoms, Licorice, Spacefill, and Surface. Use the per-component dropdown when you need a more specific representation or are styling a ligand, water, ion, or custom element.

Representation reference

Representation	What it emphasizes	Typical use
Cartoon / Ribbon	Fold and secondary structure	Proteins and nucleic acids
Ball & Stick	Atoms, bonds, and local geometry	Ligands, residues, measurement context
Licorice	Bonds with reduced atom volume	Dense atomic detail
Spacefill (CPK)	Van der Waals volume and packing	Steric fit and pocket occupancy
Surface	Smooth molecular envelope	Overall shape and pocket context
Mol. Surface	Detailed molecular boundary	Accessibility and molecular envelope inspection
Backbone	Simplified chain trace	Large polymers and comparisons
Line	Lightweight bond network	Large systems and contextual detail
Point	Minimal atom markers	Very large or dense systems
Putty	Variable-width backbone trace	B-factor or flexibility-oriented views
Ellipsoid	Anisotropic displacement	Structures with appropriate displacement data

Not every representation is equally meaningful for every component. If a change produces an empty or confusing view, restore a standard choice such as Cartoon / Ribbon for protein or Ball & Stick for ligand.

Change a color scheme

In Display, locate the component you want to recolor.

Open its color-scheme control.

Choose a scheme that encodes a property relevant to the current question. For secondary structure, the control is labeled Sec. Struct.

If you choose Uniform, select a color with sufficient contrast against the background and nearby components.

Color scheme	Meaning	Good use
Element	Standard color by atomic element	Ligands and atom-level inspection
Chain	A distinct color for each chain	Oligomers and interfaces
Residue Name	Color by residue identity	Sequence composition and local chemistry
Secondary Structure	Color by helix, sheet, and other structural class	Protein fold communication
Hydrophobicity	Color by hydrophobic character	Binding surfaces and pockets
Sequence ID	Color along sequence position	Following the chain from start to end
Uniform	One color selected by you	Visual emphasis and controlled comparison

Build a readable scene

A professional scene usually has one dominant subject and one or two supporting layers.

Choose a neutral or high-contrast background.

Give the main protein a simple representation and restrained color.

Give the ligand or residue of interest more atomic detail and stronger contrast.

Hide or soften water, ions, or secondary structures unless they answer the question.

Use interaction lines, measurements, and labels sparingly.

Check the scene at the final export size before presenting it.

Color is most useful when it carries one consistent meaning. Avoid using several unrelated color schemes in the same scene unless you explain them explicitly.

Common scene recipes

Protein–ligand overview

Protein: Cartoon / Ribbon, Secondary Structure or a muted Uniform color.
Ligand: Ball & Stick, Element.
Water: hidden initially.
Camera: Fit → All (reset), then rotate to expose the ligand.

Binding-site review

Protein: Ribbon with Show Atoms + Ribbon enabled.
Ligand: Ball & Stick or Spacefill (CPK), Element.
Nearby residues: a custom element or surroundings component in Ball & Stick.
Interactions: enable only the types being discussed.

Chain comparison

Protein: Cartoon / Ribbon, Chain.
Ligands: Ball & Stick, Element.
Hierarchy: hide chains not included in the comparison.
Camera: use the same orientation when comparing saved scenes.

Avoid these mistakes

Do not use a surface as the only representation if you need to discuss residue-level geometry.
Do not hide a component and assume its data was removed; visibility is reversible.
Do not choose an atom-level representation for an entire large simulation unless the added detail is necessary.
Do not reuse nearly identical uniform colors for components that must be distinguished.
Do not change the active structure accidentally when several structures are loaded.