Equilibrium denaturation of recombinant human FK binding protein in urea.


The equilibrium folding behavior of recombinant human FK-binding protein, a peptidyl-prolyl cis-trans-isomerase, was examined by urea-induced denaturation using probes of protein structure including intrinsic tryptophan fluorescence, second-derivative UV absorbance, CD, and NMR. All optical probes of protein structure indicate that FKBP is capable of folding reversibly. The second-derivative UV absorbance and CD probes of the structure exhibited urea denaturation transitions at approximately 4.3 M urea. The fluorescence of the single protein tryptophan is quenched in the folded state. During the unfolding-folding transition, the unquenching of tryptophan fluorescence occurs at a slightly lower urea concentration (3.9 M urea) than the changes observed for the other optical probes of folding. These probes of structure demonstrate little dependence on protein concentration in the range of 0.2- approximately 3 mg/mL across the urea-induced denaturation transition. The reversibility of the unfolding-folding transition was confirmed from two-dimensional 15N/1H heteronuclear single-quantum coherence (HSQC) spectra of [U-15N]FKBP. In addition, the native-denatured transitions for 57 individual amino acids were determined from an analysis of these spectra acquired at different urea concentrations. Analysis of the transitions for all clearly observable HSQC cross peaks for residues distributed throughout the protein and comparison to the optical folding transitions, indicate that FKBP global folding is consistent with a two-state process. Although direct measurement of FKBP catalytic activity in urea was complex, enzyme activity was observed up to the beginning of the FKBP urea-denaturation transition.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 5283, 5284, 5285, 5286 Extra Details: unfolding-folding transition; optical probes of folding;,global folding; two-state process; enzyme activity

Submission Details

ID: GsHUahyV

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:29 p.m.

Version: 1

Publication Details
Egan DA;Logan TM;Liang H;Matayoshi E;Fesik SW;Holzman TF,Biochemistry (1993) Equilibrium denaturation of recombinant human FK binding protein in urea. PMID:7680574
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 Peptidyl-prolyl cis-trans isomerase FKBP1A P62942 FKB1A_HUMAN
100.0 Peptidyl-prolyl cis-trans isomerase FKBP1A P62943 FKB1A_RABIT
97.2 Peptidyl-prolyl cis-trans isomerase FKBP1A P18203 FKB1A_BOVIN
97.2 Peptidyl-prolyl cis-trans isomerase FKBP1A P26883 FKB1A_MOUSE
97.2 Peptidyl-prolyl cis-trans isomerase FKBP1A Q62658 FKB1A_RAT