Sodium Sulphate Reactivates a Protein A Minidomain with a Short Elastin 
-Turn
Authors: Reiersen H.; Rees A.R.
Source: Biochemical and Biophysical Research Communications, Volume 276, Number 3, October 2000 , pp. 899-904(6)
Publisher: Academic Press
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Abstract:
Elastin polymer sequences derived from muscle exhibit temperature and salt-induced reversible contractions and expansions. A folded and contracted -turn helical elastin structure is stabilised by increased intramolecular hydrophobic interactions. We have generated a switchable binding protein by inserting a typical elastin turn sequence, GVPGVG, between the two IgG-binding helices of an engineered globular minidomain from Protein A. This mutant showed increased binding of IgG-molecules compared to the wild-type sequence in the presence of sodium sulphate, as measured by surface plasmon resonance spectroscopy. Analysis by circular dichroism revealed a salt-induced folding of the mutant minidomain to a native type I -turn, likely stabilised as a result of the two interacting dehydrated valines across the -turn. Since sodium sulphate can be successfully used to regulate the folding/unfolding or binding/dissociation of this minidomain, this suggests an alternative protein purification method. Copyright 2000 Academic Press.
Keywords:
affinity;
-turn;
Biacore;
CD;
elastin;
folding;
helix;
Protein A;
sulphate;
water
Language: English
Document Type: Research article
Affiliations: Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom:
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