3G1E

X-ray crystal structure of coil 1A of human vimentin

Summary for 3G1E

• Entry DOI: 10.2210/pdb3g1e/pdb
• Related: 1GK4 1GK6 1GK7
• Descriptor: Vimentin (2 entities in total)
• Functional Keywords: dimeric parallel coiled coil, acetylation, coiled coil, host-virus interaction, intermediate filament, phosphoprotein, structural protein
• Cellular location: Cytoplasm : P08670
• Total number of polymer chains: 2
• Total formula weight: 8968.23

Authors

Meier, M.,Padilla, G.P.,Herrmann, H.,Wedig, T.,Hergt, M.,Patel, T.R.,Stetefeld, J.,Aebi, U.,Burkhard, P. (deposition date: 2009-01-29, release date: 2009-05-05, Last modification date: 2024-11-06)

Primary citation

Meier, M.,Padilla, G.P.,Herrmann, H.,Wedig, T.,Hergt, M.,Patel, T.R.,Stetefeld, J.,Aebi, U.,Burkhard, P.
Vimentin coil 1A-A molecular switch involved in the initiation of filament elongation.
J.Mol.Biol., 390:245-261, 2009

PubMed Abstract: 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.

PubMed: 19422834
DOI: 10.1016/j.jmb.2009.04.067

Experimental method

X-RAY DIFFRACTION (1.83 Å)