Properties and crystal structure of a beta-barrel folding mutant.


A mutant of a beta-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. Study holds ProTherm entries: 8629, 8630, 8631, 8632 Extra Details: additive : EDTA(0.1 mM), beta-barrel protein; hydrogen bond; van der Waals interactions;,solvent accessible surface; entropic destabilization

Submission Details


Submitter: Connie Wang

Submission Date: April 24, 2018, 8:36 p.m.

Version: 1

Publication Details
Ropson IJ;Yowler BC;Dalessio PM;Banaszak L;Thompson J,Biophys. J. (2000) Properties and crystal structure of a beta-barrel folding mutant. PMID:10692339
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