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3g1e
From Proteopedia
| 3g1e, resolution 1.83Å () | |||||||||
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| Non-Standard Residues: | , | ||||||||
| Related: | 1gk7, 1gk6, 1gk4 | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
X-ray crystal structure of coil 1A of human vimentin
Interestingly, our previously published structure of the coil 1A fragment of the human intermediate filament protein vimentin turned out to be a monomeric alpha-helical coil instead of the expected dimeric coiled coil. However, the 39-amino-acid-long helix had an intrinsic curvature compatible with a coiled coil. We have now designed four mutants of vimentin coil 1A, modifying key a and d positions in the heptad repeat pattern, with the aim of investigating the molecular criteria that are needed to stabilize a dimeric coiled-coil structure. We have analysed the biophysical properties of the mutants by circular dichroism spectroscopy, analytical ultracentrifugation and X-ray crystallography. All four mutants exhibited an increased stability over the wild type as indicated by a rise in the melting temperature (T(m)). At a concentration of 0.1 mg/ml, the T(m) of the peptide with the single point mutation Y117L increased dramatically by 46 degrees C compared with the wild-type peptide. In general, the introduction of a single stabilizing point mutation at an a or a d position did induce the formation of a stable dimer as demonstrated by sedimentation equilibrium experiments. The dimeric oligomerisation state of the Y117L peptide was furthermore confirmed by X-ray crystallography, which yielded a structure with a genuine coiled-coil geometry. Most notably, when this mutation was introduced into full-length vimentin, filament assembly was completely arrested at the unit-length filament (ULF) level, both in vitro and in cDNA-transfected cultured cells. Therefore, the low propensity of the wild-type coil 1A to form a stable two-stranded coiled coil is most likely a prerequisite for the end-to-end annealing of ULFs into filaments. Accordingly, the coil 1A domains might "switch" from a dimeric alpha-helical coiled coil into a more open structure, thus mediating, within the ULFs, the conformational rearrangements of the tetrameric subunits that are needed for the intermediate filament elongation reaction.
Vimentin coil 1A-A molecular switch involved in the initiation of filament elongation., Meier M, Padilla GP, Herrmann H, Wedig T, Hergt M, Patel TR, Stetefeld J, Aebi U, Burkhard P, J Mol Biol. 2009 Jul 10;390(2):245-61. Epub 2009 May 5. PMID:19422834
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
About this Structure
3G1E is a 2 chains structure. Full crystallographic information is available from OCA.
Reference
- Meier M, Padilla GP, Herrmann H, Wedig T, Hergt M, Patel TR, Stetefeld J, Aebi U, Burkhard P. Vimentin coil 1A-A molecular switch involved in the initiation of filament elongation. J Mol Biol. 2009 Jul 10;390(2):245-61. Epub 2009 May 5. PMID:19422834
- Georgakopoulou S, Moller D, Sachs N, Herrmann H, Aebi U. Near-UV circular dichroism reveals structural transitions of vimentin subunits during intermediate filament assembly. J Mol Biol. 2009 Feb 20;386(2):544-53. Epub 2008 Dec 30. PMID:19136013
Page seeded by OCA on Sat Jul 4 18:07:48 2009
