3TRT: Crystal structure of stabilised vimentin coil2 fragment

Cytoskeletal intermediate filaments (IFs) assemble from the elementary dimers based on a segmented alpha-helical coiled-coil (CC) structure. Crystallographic studies of IF protein fragments remain the main route to access their atomic structure. To enable crystallization, such fragments must be sufficiently short. As a consequence, they often fail to assemble into the correct CC dimers. In particular, human vimentin fragment D3 corresponding to the first half of coil2 (residues 261-335) stays monomeric in solution. We have induced its dimerization via introducing a disulfide link between two cysteines engineered in the hydrophobic core of the CC close to its N-terminus. The 2.3 A crystal structure of the D3st (stabilized) fragment reveals a mostly parallel alpha-helical bundle structure in its N-terminal half which smoothly continues into a left-handed CC towards the C-terminus. This provides a direct evidence for a continuously alpha-helical structure of the coil2 segment and disproves the previously suggested existence of linker L2 separating it into two left-handed CCs. The general principles of CC dimer stabilization by disulfide introduction are also discussed.
PDB ID: 3TRTDownload
MMDB ID: 96907
PDB Deposition Date: 2011/9/10
Updated in MMDB: 2017/11
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 3TRT: dimeric; determined by author and by software (PISA)
Molecular Components in 3TRT
Label Count Molecule
Proteins (2 molecules)
Vimentin(Gene symbol: VIM)
Molecule annotation
Chemicals (8 molecules)
* Click molecule labels to explore molecular sequence information.

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