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Keratin homogeneity in the tail feathers of Pavo cristatus and Pavo cristatus mut. alba.

Pabisch S, Puchegger S, Kirchner HO, Weiss IM, Peterlik H - J. Struct. Biol. (2010)

Bottom Line: In the final structure, the crystalline beta-cores are fixed by the rest of the keratin molecule.The hydrophobic residues of the beta-core are locked into a zip-like arrangement.Structurally there is no difference between the blue and the white bird.

View Article: PubMed Central - PubMed

Affiliation: University of Vienna, Faculty of Physics, Strudlhofgasse 4, A-1090 Vienna, Austria.

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Structural change from the calamus to the central region: close to the calamus, (a), the β-sheets are misoriented with respect to the filament axis. Away from the calamus, (b), they are increasingly aligned and form a highly oriented structure with filament axis and lateral packing being perfectly perpendicular. The grey bars symbolize the outer parts of the molecule, which are not organized in pleated sheets. Both the diameter of the filaments and their distance decreases.
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fig9: Structural change from the calamus to the central region: close to the calamus, (a), the β-sheets are misoriented with respect to the filament axis. Away from the calamus, (b), they are increasingly aligned and form a highly oriented structure with filament axis and lateral packing being perfectly perpendicular. The grey bars symbolize the outer parts of the molecule, which are not organized in pleated sheets. Both the diameter of the filaments and their distance decreases.

Mentions: For the structural development we propose therefore the model of Fig. 9: during growth, the pairs of β-sheets forming the filament are already present, but their initial orientation with respect to the helix is not well fixed over the first 50 mm from the calamus. Beyond they fall into a highly aligned and oriented structure. The half-widths of both the axial and lateral reflections decrease. The strong increase in alignment is accompanied by only a small shortening of the axial repeat unit, and no change of the intersheet distance. This leads to the conclusion that topologically the crystalline beta structure of the strands is formed early on. Only some small rotations are needed to fix the structure in a zip-like mechanism, where the sidechains perfectly interleave along the filament axis (Fraser and Parry, 2008). The high concentration of hydrophobic residues between the two strands and their interaction is important for the assembly process. They stabilize the final structure (Fraser and Parry, 2008).


Keratin homogeneity in the tail feathers of Pavo cristatus and Pavo cristatus mut. alba.

Pabisch S, Puchegger S, Kirchner HO, Weiss IM, Peterlik H - J. Struct. Biol. (2010)

Structural change from the calamus to the central region: close to the calamus, (a), the β-sheets are misoriented with respect to the filament axis. Away from the calamus, (b), they are increasingly aligned and form a highly oriented structure with filament axis and lateral packing being perfectly perpendicular. The grey bars symbolize the outer parts of the molecule, which are not organized in pleated sheets. Both the diameter of the filaments and their distance decreases.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2977532&req=5

fig9: Structural change from the calamus to the central region: close to the calamus, (a), the β-sheets are misoriented with respect to the filament axis. Away from the calamus, (b), they are increasingly aligned and form a highly oriented structure with filament axis and lateral packing being perfectly perpendicular. The grey bars symbolize the outer parts of the molecule, which are not organized in pleated sheets. Both the diameter of the filaments and their distance decreases.
Mentions: For the structural development we propose therefore the model of Fig. 9: during growth, the pairs of β-sheets forming the filament are already present, but their initial orientation with respect to the helix is not well fixed over the first 50 mm from the calamus. Beyond they fall into a highly aligned and oriented structure. The half-widths of both the axial and lateral reflections decrease. The strong increase in alignment is accompanied by only a small shortening of the axial repeat unit, and no change of the intersheet distance. This leads to the conclusion that topologically the crystalline beta structure of the strands is formed early on. Only some small rotations are needed to fix the structure in a zip-like mechanism, where the sidechains perfectly interleave along the filament axis (Fraser and Parry, 2008). The high concentration of hydrophobic residues between the two strands and their interaction is important for the assembly process. They stabilize the final structure (Fraser and Parry, 2008).

Bottom Line: In the final structure, the crystalline beta-cores are fixed by the rest of the keratin molecule.The hydrophobic residues of the beta-core are locked into a zip-like arrangement.Structurally there is no difference between the blue and the white bird.

View Article: PubMed Central - PubMed

Affiliation: University of Vienna, Faculty of Physics, Strudlhofgasse 4, A-1090 Vienna, Austria.

Show MeSH