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Amyloid—a state in many guises: Survival of the fittest fibril fold
Author(s) -
Pedersen Jesper S.,
Otzen Daniel E.
Publication year - 2008
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.073127808
Subject(s) - fibril , amyloid fibril , protein folding , beta sheet , chemistry , biophysics , protein aggregation , protein structure , amyloid (mycology) , polymorphism (computer science) , crystallography , biology , biochemistry , amyloid β , allele , gene , medicine , inorganic chemistry , disease , pathology
Under appropriate conditions, essentially all proteins are able to aggregate to form long, well‐ordered and β‐sheet‐rich arrays known as amyloid‐like fibrils. These fibrils consist of varying numbers of intertwined protofibrils and can for any given protein exhibit a wealth of different forms at the ultrastructural level. Traditionally, this structural variability or polymorphism has been attributed to differences in the assembly of a common protofibril structure. However, recent work on glucagon, insulin, and the Aβ peptide suggests that this polymorphism can occur at the level of secondary structure. Simple variations in either solvent conditions such as temperature, protein concentration, and ionic strength or external mechanical influences such as agitation can lead to formation of fibrils with markedly different characteristics. In some cases, these characteristics can be passed on to new fibrils in a strain‐specific manner, similar to what is known for prions. The preferred structure of fibrils formed can be explained in terms of selective pressure and survival of the fittest; the most populated types of fibrils we observe at the end of an experiment are those that had the fastest overall growth rate under the given conditions. Fibrillar polymorphism is probably a consequence of the lack of structural restraints on a nonfunctional conformational state.