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Chemical colloids versus biological colloids: a comparative study for the elucidation of the mechanism of protein fiber formationFiber formation from murine serum amyloid A1 (SAA) was compared to the linear aggregation and fiber formation of colloidal gold particles. Here we report the similarities of these processes. Upon incubation with acetic acid, SAA misfolds and adopts a new conformation, which we termed saa. saa apparently is less soluble than SAA in aqueous solution; it aggregates and forms nucleation units and then fibers. The fibers appear as a string of the nucleation units. Additionally, an external electric field promotes saa fiber formation. These properties of saa are reminiscent of colloidal gold formation from gold ions and one-dimensional aggregation of the gold colloids. Colloidal gold particles were also found to be capable of aggregating one-dimensionally under an electric field or in the presence of polylysine. These gold fibers resembled in structure that of saa fibers. In summary, protein aggregation and formation of fibers appear to follow the generalized principles derived in colloidal science for the aggregation of atoms and molecules, including polymers such as polypeptides. The analysis of colloidal gold formation and of one-dimensional aggregation provides a simple model system for the elucidation of some aspects of protein fiber formation.
Document ID
20050184408
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Xu, Shaohua
(NASA Kennedy Space Center Cocoa Beach, FL United States)
Wu, David
Arnsdorf, Morton
Johnson, Robert
Getz, Godfrey S.
Cabana, Veneracion G.
Date Acquired
August 23, 2013
Publication Date
April 12, 2005
Publication Information
Publication: Biochemistry
Volume: 44
Issue: 14
ISSN: 0006-2960
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: R44GM
Distribution Limits
Public
Copyright
Other

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