Max Planck Institute for Molecular Genetics

	Group leader: Francois Franceschi

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Large subunit (50S) structure:

We used Deinococcus radiodurans, a Gram-positive bacteria, to determined the structure of the large ribosomal subunit (50S). Deinococcus radiodurans has been shown to be the most radiation resistant organism known to date. Because its ribosomes and ribosomal subunits are also radiation resistant, ribosomal crystals can withstand the synchrotron radiation used during the data collection process fairly well.

Micrograph showing a characteristic
tetrad of D. radiodurans cells

D. radiodurans is a Gram-positive, non-motile, non-sporulating bacterium. It was originally identified as a contaminant of irradiated canned meat. Later, it was isolated from environments that are either very rich or extremely poor in organic nutrients, such as soil, weathered granite in a dry Antarctic valley, room dust, nuclear waste, and irradiated medical instruments. It can survive under conditions that cause DNA damage, such as hydrogen peroxide, and ionizing or ultraviolet radiation. This bacteria contains systems for DNA repair, DNA damage export, desiccation, starvation recovery, and genetic redundancy.

Large subunit (50S)

The crystals of the 50S ribosomal subunit from Deinococcus radiodurans reach an average size of 200x150x50µm. Data are collected from flash-frozen crystals at cryo-conditions (90K) with bright synchrotron radiation. Cell constants: a=170Å, b=410Å and c=697Å, space group I222.

Crystals of D. radiodurans 50S. The cristallization conditions for this new type of crystal were developed in our group.

The large subunit (50S) from Deinococcus radiodurans contains 33 different proteins and two rRNA chains (23S and 5S rRNA). The ribosomal rRNA accounts for about two thirds of the mass.

If you want to see a rotating model click on the figure (800 kb)

The structure of the 50S subunit from D. radiodurans showing the L1-arm, the L7/12 arm, and the central protuberance (CP) containing the 5S rRNA. The side of the structure facing the viewer contacts the 30S subunit. Turquois, rRNA. Other colors, proteins.

A description of the 50S structure can be found in:

High resolution structure of the large ribosomal subunit from a meshophilic eubacterium. Harms, J., Schlünzen, F., Zarivach, R., Bashan, A., Gat, S., Agmon, I., Bartels, H., Franceschi, F. and Yonath, A. Cell 107, 679-688 (2001).

The atomic coordinates can be found in the Protein data bank (PDB)
PDB ID: 1KC9

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