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β‐sheet folding of 11‐kDa fibrillogenic polypeptide is completely aggregation driven
Author(s) -
Topilitalya I.,
Ermolenkov Vladimir V.,
Higashiya Seiichiro,
Welch John T.,
Lednev Igor K.
Publication year - 2007
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20730
Subject(s) - chemistry , folding (dsp implementation) , protein folding , biophysics , protein aggregation , beta sheet , biochemistry , protein structure , electrical engineering , biology , engineering
A de novo polypeptide GH 6 [(GA) 3 GY(GA) 3 GE] 8 GAH 6 (YE8) was designed and genetically engineered to form antiparallel β‐strands of GAGAGA repeats. Modulation of pH enables control of solubility, folding, and aggregation of YE8 by control of the overall polypeptide charge, a consequence of the protonation or deprotonation of the glutamic acid and histidine residues. YE8 exhibits all the major properties of a fibrillogenic protein providing an excellent model for detailed study of the fibrillation. At neutral pH, YE8 is soluble in disordered form, yet at pH 3.5 folds into a predominantly β‐sheet conformation that is fibrillogenic. Atomic force microscopy and transmission electron microscopy indicated the formation of fibrillar aggregates on well‐defined, hydrophobic surfaces. The β‐sheet folding of YE8 exhibited a lag phase that could be eliminated by seeding or stirring. The strong dependence of lag time on polypeptide concentration established the limiting step in aggregation as initiation of β‐sheet folding. © 2007 Wiley Periodicals, Inc. Biopolymers 86: 261–264, 2007. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com