Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 2 de 2
Filter
Add more filters










Database
Language
Publication year range
1.
Acta Histochem ; 108(3): 215-9, 2006.
Article in English | MEDLINE | ID: mdl-16714052

ABSTRACT

Protofibrils (PFs) represent the earliest fibrillar species that occur in the course of amyloid fibril formation. Using apomyoglobin, we report here that PFs arise from a multi-step reaction and that they are preceded by an ensemble of non-fibrillar particles (NFPs). These intermediate aggregates encompass nascent elements of amyloid structure and can act as seeds in PF formation. Taken together with the observation that PFs often protrude from NFPs, our data suggest that PFs form by a random nucleation mechanism in which the polypeptide chains sample many different aggregated conformations. Once the appropriate structural characteristics are acquired, PFs are formed by addition of further polypeptide chains.


Subject(s)
Amyloid/chemistry , Apoproteins/chemistry , Myoglobin/chemistry , Amyloid/ultrastructure , Animals , Horses , Microscopy, Atomic Force , Microscopy, Electron, Transmission , Models, Molecular , Protein Conformation , Protein Folding
2.
Proc Natl Acad Sci U S A ; 100(26): 15463-8, 2003 Dec 23.
Article in English | MEDLINE | ID: mdl-14665689

ABSTRACT

Observations that beta-sheet proteins form amyloid fibrils under at least partially denaturing conditions has raised questions as to whether these fibrils assemble by docking of preformed beta-structure or by association of unfolded polypeptide segments. By using alpha-helical protein apomyoglobin, we show that the ease of fibril assembly correlates with the extent of denaturation. By contrast, monomeric beta-sheet intermediates could not be observed under the conditions of fibril formation. These data suggest that amyloid fibril formation from apomyoglobin depends on disordered polypeptide segments and conditions that are selectively unfavorable to folding. However, it is inevitable that such conditions often stabilize protein folding intermediates.


Subject(s)
Myofibrils/chemistry , Myoglobin/chemistry , Myoglobin/metabolism , Peptides/metabolism , Amino Acid Sequence , Animals , Horses , Molecular Sequence Data , Peptides/chemistry , Protein Denaturation , Protein Folding , Spectroscopy, Fourier Transform Infrared , Thermodynamics , X-Ray Diffraction
SELECTION OF CITATIONS
SEARCH DETAIL
...