Fibril formation from recombinant human serum amyloid A

Toshiyuki Yamada, Barbara Kluve-Beckerman, Juris J. Liepnieks, Merrill D. Benson

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66 Scopus citations

Abstract

Three isotypes of human serum amyloid A (SAA), SAA1, SAA2β, and SAA4 were expressed at high levels in Escherichia coli (E. coli) using a pET vector expression system. Each SAA cDNA was ligated to the vector pET-21a(+) and transformed into E. coli, strain BL21(DE3)pLysS. Expression conditions required high concentrations of antibiotics in order to obtain a high ratio of synthesized SAA to total E. coli proteins. Each recombinant SAA (rSAA) was purified by molecular sieve chromatography followed by chromatofocusing or hydrophobic interaction chromatography. The yield of purified was 5-10 mg per 11 of culture. When subjected to in vitro fibril forming conditions, rSAA1 formed amyloid-like fibrils confirmed by Congo red staining and electron microscopy. In contrast, rSAA2β and rSAA4 showed negative Congo red staining and curvilinear or flattened fibrillar structures on electron microscopy. This suggests that SAA1 has greater potential for forming amyloid fibrils than either SAA2β or SAA4.

Original languageEnglish (US)
Pages (from-to)323-329
Number of pages7
JournalBBA - Molecular Basis of Disease
Volume1226
Issue number3
DOIs
StatePublished - Jul 18 1994

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Keywords

  • Amyloid fibril
  • Isotype
  • Recombinant
  • Serum amyloid A

ASJC Scopus subject areas

  • Biophysics
  • Molecular Biology
  • Molecular Medicine

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