Folding of a predominantly beta-structure protein: rat intestinal fatty acid binding protein.


The equilibrium and kinetic properties of the unfolding-refolding transitions of Escherichia coli derived rat intestinal fatty acid binding protein have been examined using several different denaturants. This protein, which contains 2 tryptophans but no prolines or cysteines, has a predominantly beta-structure: its 10 antiparallel beta-strands are organized into 2 orthogonal sheets surrounding a large solvent-filled internal cavity. For urea and guanidine hydrochloride, the completely reversible transition was monitored by circular dichroism, absorbance, and fluorescence spectroscopy. Each of these data sets was best fit by a simple, two-state model involving only native and unfolded forms. However, linear extrapolation to determine the free energy of folding in the absence of denaturant resulted in different values for the free energy of folding depending upon which denaturant was used. When fluorescence was used to monitor the transition, the extrapolated free energy estimates for the two denaturants were markedly different: 10.03 +/- 0.24 kcal mol-1 for urea versus 5.22 +/- 0.33 kcal mol-1 for guanidine hydrochloride. The midpoints of these transitions were 5.51 and 1.36 M, respectively. The transition caused by either denaturant as monitored by circular dichroism and absorbance spectroscopy was virtually coincident with that monitored by fluorescence, further supporting the assignment of a two-state model for the equilibrium results. The addition of a 2-fold molar excess of ligand (oleate) increased the extrapolated estimates approximately 2.5 kcal mol-1 for both denaturants.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 3690, 3691, 3692, 3693, 3694, 3695 Extra Details: additive : EDTA(0.1 mM), beta-structure; two-state model; sequential unfolding;,multiple pathways

Submission Details

ID: LccbnDpi

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:22 p.m.

Version: 1

Publication Details
Ropson IJ;Gordon JI;Frieden C,Biochemistry (1990) Folding of a predominantly beta-structure protein: rat intestinal fatty acid binding protein. PMID:2271603
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Fatty acid-binding protein, brain P55051 FABP7_RAT
97.0 Fatty acid-binding protein, brain P51880 FABP7_MOUSE
100.0 Fatty acid-binding protein, intestinal P02693 FABPI_RAT
92.4 Fatty acid-binding protein, intestinal P55050 FABPI_MOUSE