Integrated Analysis of Molecular Assemblies using Chimera
A Demonstration with Alpha Crystallin

24 copies of alpha crystallin for oligomer seen by electron microscopy.	Human alpha crystallin is 2 beta sheets.

Various crystal structures show several biological dimerization modes.	C-terminal tail binds to edge of beta-sheet. Binds in 180 degree flipped orientation too. Binding sequence is palindrome.	Side-by-side beta sheet dimer.

Beta-sheet dimer observed with 3 different registrations in crystals and NMR. Some literature suggest all are present allowing different oligomers to form.		Small-angle x-ray scattering in solution shows only one registration is present at physiological conditions (NMR registration).

Shifted human dimer with C-terminal tails for building 24-mer.

Fit dimer to map.
Determine map symmetry and replicate fit dimer.
Adjust tails by matching to crystal tail dimer and using energy minimization.
Show hydrophobicity SES surfaces.
Hide C-terminal tails to show very hydrophobic groove -- oligmer believed to
  disassemble to bind unfolded proteins -- exposes these grooves.
Show M jannashii sHSP octahedral symmetry, 1shs.
Morph between 1shs and the 3l1g fit created in the demo.

Mention that higher resolution 9A EM map and fit is about to be published
  -- will be interesting to see how far off our quick model is.