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Twelve machines, grouped by the job they do. Each page shows the machine in 3D, explains how it works and links every number to its source.

Rotary motors

ATP synthase, rendered from PDB coordinates

A proton-driven rotary motor that makes most of the cell's ATP

~100 turns/s turn rate in mitochondria

Bacterial flagellar motor, rendered from PDB coordinates

Bacterial flagellar motor

An ion-driven, reversible rotary motor that turns the bacterial flagellum

1,260 pN·nm stall torque, e. coli (fully induced)

Walkers and crawlers

Kinesin, rendered from PDB coordinates

Walks toward the microtubule plus end in 8 nm steps, one ATP per step

8 nm step size

Myosin, rendered from PDB coordinates

Swings a lever arm on actin to pull filaments and haul cargo

about 11 nm stroke per head, muscle myosin

Dynein, rendered from PDB coordinates

A ring of six ATPases that walks to the microtubule minus end

8 nm most frequent step

Readers and writers

Ribosome, rendered from PDB coordinates

Reads mRNA and builds the matching protein chain

12-17 amino acids per second elongation rate in e. coli

RNA polymerase II, rendered from PDB coordinates

RNA polymerase II

Copies a DNA gene into messenger RNA, one base at a time

Folding

GroEL–GroES, rendered from PDB coordinates

An ATP-driven cage that holds one protein while it folds

14 GroEL + 7 GroES subunits

Recycling

Proteasome, rendered from PDB coordinates

An ATP-driven shredder that pulls tagged proteins apart

2.5 MDa mass of the holoenzyme

Pumps

SERCA calcium pump, rendered from PDB coordinates

SERCA calcium pump

Burns one ATP to push two calcium ions out of the cytoplasm

2 calcium ions per atp

Switches

Hemoglobin, rendered from PDB coordinates

Four-part oxygen carrier that loads and unloads as a single switch

4 chains in the working unit

Defence and editing

Cas9, rendered from PDB coordinates

RNA-guided nuclease that finds one DNA sequence and cuts both strands

1368 residues