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Amyloid fibrillogenesis of silkmoth chor ... -crystalline intermediate phase
Amyloid fibrillogenesis of silkmoth chorion protein peptide-analogues via a liquid-crystalline intermediate phase.
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Chorion, the major component of silkmoth eggshell, consists of the A and B classes of low-molecular weight structural proteins. Chorion protects the oocyte and the developing embryo from environmental hazards and this is due to the extraordinary physical and chemical properties of its constituent proteins. We have shown previously [FEBS Lett. 479 (2000) 141; 499 (2001) 268] that peptide-analogues of the A and B classes of chorion proteins form amyloid fibrils under a variety of conditions, which led us to propose that silkmoth chorion is a natural, protective amyloid. In this work, we present data showing conclusively that, the first main step of amyloid-like fibrillogenesis of chorion peptides is the formation of nuclei of liquid crystalline nature, which is reminiscent of spider-silk formation. We show that these liquid-crystalline nuclei (spherulites) 'collapse'/deteriorate to form amyloid fibrils in a spectacular manner, important, it seems, for chorion morphogenesis and amyloid fibrillogenesis in general. The molecular 'switch' causing this spectacular transformation is, most probably, a conformational transition to the structure of chorion peptides, from a left-handed parallel beta-helix to an antiparallel beta-pleated sheet. Apparently, these peptides were suitably designed to play this role, after millions of years of molecular evolution.
Hamodrakas SJ, Hoenger A, Iconomidou VA
Journal of structural biology
2004-03-01 00:00
145
3
226-35
Amino Acid Sequence,Amyloid,Animals,Bombyx,Chorion,Coloring Agents,Congo Red,Methanol,Micelles,Microscopy, Electron,Molecular Sequence Data,Peptides,Polymers,Protein Structure, Secondary,Spectrophotometry, Infrared,X-Ray Diffraction,Amyloid,Coloring Agents,Micelles,Peptides,Polymers,liquid crystal polymer,Congo Red,Methanol
Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Athens 157 01, Greece shamodrccuoagr
J. Struct. Biol.
1047-8477
10.1016/j.jsb.2003.10.004
S1047847703002168
547
True
14960373
