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Dimorphic aggregation behavior of a fusion polypeptide incorporating a stable protein domain (EGFP) with an amyloidogenic sequence (retroCspA)
Author(s) -
Sharma Swati,
Guptasarma Purnananda
Publication year - 2008
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2008.05.008
Subject(s) - green fluorescent protein , thioflavin , fusion protein , protein aggregation , biophysics , chemistry , fusion , fluorescence , protein folding , amyloid (mycology) , sequence (biology) , fibril , protein domain , biochemistry , recombinant dna , biology , medicine , inorganic chemistry , linguistics , philosophy , physics , disease , pathology , quantum mechanics , alzheimer's disease , gene
We describe the behavior of a polypeptide consisting of the genetic fusion of a structurally stable single‐domain protein, EGFP (an analog of the green fluorescent protein) with an amyloidogenic sequence, retroCspA (known to readily form amyloid fibrils). Refolding of the fusion protein through single‐step removal of denaturant and salt results in precipitation into amyloid aggregates displaying fibrillar morphology, thioflavin T binding as well as green fluorescence. Refolding through step‐wise reduction of denaturant concentration in the presence of salt yields a soluble aggregate containing a folded, thermally‐stable, non‐fluorescent EGFP domain. Together, these results indicate that retroCspA forces the fusion protein to aggregate; however, the EGFP domain remains folded in a native‐like structural format in both soluble aggregates and precipitates.