Mol MicroErhardt lab

Molecular movies

Animations of the flagellum, the stator unit, the injectisome, the conjugation machinery and the Zorya defence system, built from experimental and predicted protein structures.

Build a flagellum tells the assembly as a scroll story; What is a flagellum? introduces it in plain language.

From chaos to a flagellum

Flagellar building blocks lie scattered among the other molecules of a crowded cell. The flagellum then assembles from the inside out: export gate, MS ring, C ring, export ATPase, rod, P and L rings, hook. After hook completion the late proteins are exported, MotA5B2 stator units form in the inner membrane and diffuse to the motor, and the rotor starts to turn.

Real structures; cytoplasm from Brownian-dynamics simulation. Timing is illustrative.Download MP4 (1280 × 720, 5.6 MB) · Full HD (1920 × 1080, 10 MB); with watermarkCite as: Erhardt lab (2026). From chaos to a flagellum. Molecular Microbiology, Humboldt-Universität zu Berlin. https://www.molmicro.hu-berlin.de/movies.html#from-chaos-to-a-flagellum. Licence: CC BY-NC 4.0

Building a flagellum (6)

Rod, hook and filament (4)

Motors (3)

Zorya anti-phage defence (2)

Injectisome and conjugation (2)

Filament growth, length and energy (5)

Costs and benefits of flagellation (2)

Short loops (10)

About the movies

The protein structures derive from cryo-EM data and AlphaFold models. The crowded cytoplasm derives from Brownian-dynamics simulations. Speeds, timing and some arrangements are simplified. The Zorya movies show a proposed model. Each description states which elements are experimental and which are modelled.

Licence

The movies are licensed under Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0). You may show, share and adapt them for non-commercial purposes, for example in teaching, talks and theses. Give the citation under each movie and state any changes. For commercial use, for example in textbooks, please contact us.

The licence covers the movies. The experimental structures come from the Protein Data Bank (data under CC0); predicted models come from AlphaFold (CC BY 4.0). The published data and models that a movie follows are named in its description.