Properties and crystal structure of a β-barrel folding mutant

Ira J. Ropson, Brian C. Yowler, Paula M. Dalessio, Leonard Banaszak, James Thompson

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

A mutant of a β-barrel protein, rat intestinal fatty acid binding protein, was predicted to be more stable than the wild-type protein due to a novel hydrogen bond. Equilibrium denaturation studies indicated the opposite: the V60N mutant protein was less stable. The folding transitions followed by CD and fluorescence were reversible and two-state for both mutant and wild- type protein. However, the rates of denaturation and renaturation of V60N were faster. During unfolding, the initial rate was associated with 75-80% of the fluorescence and all of the CD amplitude change. A subsequent rate accounted for the remaining fluorescence change for both proteins; thus the intermediate state lacked secondary structure. During folding, one rate was detected by both fluorescence and CD after an initial burst phase for both wild-type and mutant. An additional slower folding rate was detected by fluorescence for the mutant protein. The structure of the V60N mutant has been obtained and is nearly identical to prior crystal structures of IFABP. Analysis of mean differences in hydrogen bond and van der Waals interactions did not readily account for the stability loss due to the mutation. However, significant average differences of the solvent accessible surface and crystallographic displacement factors suggest entropic destabilization.

Original languageEnglish (US)
Pages (from-to)1551-1560
Number of pages10
JournalBiophysical Journal
Volume78
Issue number3
StatePublished - Mar 2000
Externally publishedYes

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Fluorescence
Mutant Proteins
Hydrogen
Fatty Acid-Binding Proteins
Proteins
Mutation

ASJC Scopus subject areas

  • Biophysics

Cite this

Ropson, I. J., Yowler, B. C., Dalessio, P. M., Banaszak, L., & Thompson, J. (2000). Properties and crystal structure of a β-barrel folding mutant. Biophysical Journal, 78(3), 1551-1560.

Properties and crystal structure of a β-barrel folding mutant. / Ropson, Ira J.; Yowler, Brian C.; Dalessio, Paula M.; Banaszak, Leonard; Thompson, James.

In: Biophysical Journal, Vol. 78, No. 3, 03.2000, p. 1551-1560.

Research output: Contribution to journalArticle

Ropson, IJ, Yowler, BC, Dalessio, PM, Banaszak, L & Thompson, J 2000, 'Properties and crystal structure of a β-barrel folding mutant', Biophysical Journal, vol. 78, no. 3, pp. 1551-1560.
Ropson IJ, Yowler BC, Dalessio PM, Banaszak L, Thompson J. Properties and crystal structure of a β-barrel folding mutant. Biophysical Journal. 2000 Mar;78(3):1551-1560.
Ropson, Ira J. ; Yowler, Brian C. ; Dalessio, Paula M. ; Banaszak, Leonard ; Thompson, James. / Properties and crystal structure of a β-barrel folding mutant. In: Biophysical Journal. 2000 ; Vol. 78, No. 3. pp. 1551-1560.
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