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Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy.

 
Name of Journal
Nature, 424: 643-650 (2003)  
 
Author
Yonekura K, Maki-Yonekura S, Namba K.  
 
Title of Article
Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy.  
 
Laboratory HP
http://www.fbs.osaka-u.ac.jp/labo/09a.html  
 
Summary

The bacterial flagellar filament is a helical propeller for bacterial locomotion. Electron cryomicroscopy and image analysis visualized its atomic structure and unveiled the precise switching mechanism of this switchable helical propeller at nano-scale.

 
 
PubMed Link
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?
cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12904785
 
 
Email for reprint request
Keiichi Namba:  
 
Description
The bacterial flagellar filament is a helical propeller for bacterial locomotion. It is a helical assembly of a single protein, flagellin, and its tubular structure is formed by 11 protofilaments in two distinct conformations, L- and R-type, for supercoiling. The X-ray crystal structure of a flagellin fragment lacking about 100 terminal residues revealed the protofilament structure, but the full filament structure is still essential for understanding the mechanism of supercoiling and polymerization. Here we report a complete atomic model of the R-type filament by electron cryomicroscopy. A density map obtained from image data up to 4 Å resolution shows the feature of -helical backbone and some large side chains. The atomic model built on the map reveals intricate molecular packing and an -helical coiled coil formed by the terminal chains in the inner core of the filament, with its intersubunit hydrophobic interactions having an important role in stabilizing the filament.
 
 
Click the image below for viewing a larger image.


Figure 1: Computer graphic representation of the assembly process of the bacterial flagellum and a swimming bacterium with a rotating bundle of the helical flagellar filaments behind the cell body. The diameter of the filament is 20 nm and the length is about 10 mm.

Figure2: Ca backbone model of the atomic structure of the flagellar filament. Side views showing the inner side (left) and outer surface (right). The amino acid sequence of each flagellin subunit is color-coded from blue for the N-terminus to red for the C-terminus.


Moving Images Collection
(JST Website)

For details, please download a movie(34 min.) here.
*Please be aware of the file size.
Medium size:
105MB QuickTime movie:320x240 pixels
Large size: 288MB MPEG-4 movie: 640x480 pixels


A Rotary NanoMachine
~Understanding the Structure and Dynamics of Bacterial Flagella~
Protonic NanoMachine Project, ERATO, Japan Science and Technology Corporation




 

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