A residual structure in unfolded intestinal fatty acid binding protein consists of amino acids that are neighbors in the native state

Ira Ropson, Joshua A. Boyer, Paula Dalessio

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Much of the recent effort in protein folding has focused on the possibility that residual structures in the unfolded state may provide an initiating site for protein folding. This hypothesis is difficult to test because of the weak stability and dynamic behavior of these structures. This problem has been simplified for intestinal fatty acid binding protein (IFABP) by incorporating fluorinated aromatic amino acids during synthesis in Escherichia coli. Only the labeled residues give signals by 19F NMR, and the 1D spectra can be assigned in both the native and unfolded states by site-directed mutagenesis. One of the two tryptophans (W82), one of the four tyrosines (Y70), and at least four of the eight phenylalanines (including F68 and F93) of IFABP are involved in a structure that is significantly populated at concentrations of urea that unfold the native structure by fluorescence and CD criteria. These residues are nonlocal in sequence and also contact each other in the native structure. Thus, a template of nativelike hydrophobic contacts in the unfolded state may serve as an initiating site for folding this β-sheet protein.

Original languageEnglish (US)
Pages (from-to)2608-2617
Number of pages10
JournalBiochemistry
Volume45
Issue number8
DOIs
StatePublished - Feb 28 2006

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Protein folding
Fatty Acid-Binding Proteins
Protein Folding
Amino Acids
Aromatic Amino Acids
Mutagenesis
Phenylalanine
Tryptophan
Escherichia coli
Tyrosine
Urea
Fluorescence
Nuclear magnetic resonance
Site-Directed Mutagenesis
Proteins

All Science Journal Classification (ASJC) codes

  • Biochemistry

Cite this

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abstract = "Much of the recent effort in protein folding has focused on the possibility that residual structures in the unfolded state may provide an initiating site for protein folding. This hypothesis is difficult to test because of the weak stability and dynamic behavior of these structures. This problem has been simplified for intestinal fatty acid binding protein (IFABP) by incorporating fluorinated aromatic amino acids during synthesis in Escherichia coli. Only the labeled residues give signals by 19F NMR, and the 1D spectra can be assigned in both the native and unfolded states by site-directed mutagenesis. One of the two tryptophans (W82), one of the four tyrosines (Y70), and at least four of the eight phenylalanines (including F68 and F93) of IFABP are involved in a structure that is significantly populated at concentrations of urea that unfold the native structure by fluorescence and CD criteria. These residues are nonlocal in sequence and also contact each other in the native structure. Thus, a template of nativelike hydrophobic contacts in the unfolded state may serve as an initiating site for folding this β-sheet protein.",
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A residual structure in unfolded intestinal fatty acid binding protein consists of amino acids that are neighbors in the native state. / Ropson, Ira; Boyer, Joshua A.; Dalessio, Paula.

In: Biochemistry, Vol. 45, No. 8, 28.02.2006, p. 2608-2617.

Research output: Contribution to journalArticle

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