Mutational effects on inclusion body formation in the periplasmic expression of the immunoglobulin VL domain REI

Winnie Chan, Larry R. Helms, Ian Brooks, Grace Lee, Sarah Ngola, Dean McNulty, Beverly Maleeff, Preston Hensley, Ronald Wetzel

Research output: Contribution to journalArticle

Abstract

Background: Inclusion body (IB) formation in bacteria is an important example of protein misassembly, a phenomenon which also includes folding-dependent aggregation in vitro and amyloid deposition in human disease. Previous studies of mutational effects in other systems implicate the stability of a folding intermediate-rather than the native state-as playing a key role in IB formation. To contribute to an understanding of the comparative biophysics of VL misassembly in different biological settings, we have studied mutation-dependent periplasmic IB formation by the VL domain REI in Escherichia coli. Results: A series of mutants were produced in periplasmic IBs, where, in all cases, the signal peptide was removed. In addition, the intradomain disulfide was clearly formed before deposition into IBs. IB formation in these mutants does not correlate with monomer/dimer equilibrium constants, but does correlate with the thermodynamic stability of the native state. Conclusions: The results implicate a late, equilibrium folding intermediate in IB formation, in contrast to the apparent involvement of transient folding intermediates in other IB systems described to date. As equilibrium unfolding intermediates have also been implicated in light chain amyloidosis and deposition diseases, IB formation may prove a useful model for these human diseases.

Original languageEnglish (US)
Pages (from-to)77-89
Number of pages13
JournalFolding and Design
Volume1
Issue number2
DOIs
StatePublished - Jan 1 1996
Externally publishedYes

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Keywords

  • Disulfide bonds
  • Folding intermediate
  • Light chain
  • Periplasmic inclusion bodies
  • Temperature-sensitive folding mutations
  • Thermodynamic stability

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine

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