Structural analysis of the C-terminal region of chicken gizzard desmin

The C-terminal sequence of chicken gizzard desmin has been examined by computer programs based on Chou-Fasman prediction of secondary structure, auto-correlation and Fourier analysis of hydrophobic residue distribution, and cross-correlation analysis of acidic and basic residues. These analyses indicate that, although parts of the desmin sequence are alpha-helical, the helical regions may not be as extensive as predicted previously. Detailed analysis of the distribution of the charged residues in the desmin sequence strongly suggests that it cannot form a tropomyosin-like coiled-coil double-helix because of the almost complete absence of stabilizing salt-bridge interactions between proximal pairs of acidic and basic residues. Although the desmin sequence does contain the tropomyosin-like hydrophobic residue distribution, differences exist in the overall distributions of hydrophobes, with clusters of these residues being found in certain regions of the desmin sequence. Analyses of the sequences of porcine desmin and vimentin reveal very similar structural characteristics for these molecules, although vimentin is predicted to have a different structure at its C-terminus.