A water mediated electrostatic interaction gives thermal stability to the "tail" region of the GrpE protein from E. coli

Andrew F. Mehl, Borries Demeler, Afaq Zraikat

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

The GrpE protein from E. coli is a homodimer with an unusual structure of two long paired α-helices from each monomer interacting in a parallel arrangement to form a "tail" at the N-terminal end. Using site-directed mutagenesis, we show that there is a key electrostatic interaction involving R57 (mediated by a water molecule) that provides thermal stability to this "tail" region. The R57A mutant showed a drop in T m of 8.5°C and a smaller ΔH u (unfolding) compared to wild-type for the first unfolding transition, but no significant decrease in dimer stability as shown through equilibrium analytical ultracentrifugation studies. Another mutant (E94A) at the dimer interface showed a decrease in ΔH u but no drop in T m for the second unfolding transition and a slight increase in dimer stability.

Original languageEnglish (US)
Pages (from-to)239-245
Number of pages7
JournalProtein Journal
Volume26
Issue number4
DOIs
StatePublished - Jun 2007

Keywords

  • Electrostatic interactions
  • GrpE
  • Oligomerization
  • Protein stability
  • Salt bridge

ASJC Scopus subject areas

  • Analytical Chemistry
  • Bioengineering
  • Biochemistry
  • Organic Chemistry

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