Linked thermal and solute perturbation analysis of cooperative domain interactions in proteins. Structural stability of diphtheria toxin.


Abstract

The temperature and guanidine hydrochloride (GuHCl) dependence of the structural stability of diphtheria toxin has been investigated by high-sensitivity differential scanning calorimetry. In 50 mM phosphate buffer at pH 8.0 and in the absence of GuHCl, the thermal unfolding of diphtheria toxin is characterized by a transition temperature (Tm) of 54.9 degrees C, a calorimetric enthalpy change (delta H) of 295 kcal/mol, and a van't Hoff to calorimetric enthalpy ratio of 0.57. Increasing the GuHCl concentration lowers the transition temperature and the calorimetric enthalpy change. At the same time, the van't Hoff to calorimetric enthalpy ratio increases until it reaches a value of 1 at 0.3 M GuHCl and remains constant thereafter. At low GuHCl concentrations (0-0.3 M), the thermal unfolding of diphtheria toxin is characterized by the presence of two transitions corresponding to the A and B domains of the protein. At higher GuHCl concentrations (0.3-1 M), the A domain is unfolded at all temperatures, and only one transition corresponding to the B domain is observed. Under these conditions, the most stable protein conformation at low temperatures is a partially folded state in which the A domain is unfolded and the B domain folded. A general model that explicitly considers the energetics of domain interactions has been developed in order to account for the stability and cooperative behavior of diphtheria toxin. It is shown that this cooperative domain interaction model correctly accounts for the temperature location as well as the shape and area of the calorimetric curves. Under physiological conditions, domain-domain interactions account for most of the structural stability of the A domain.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 3645, 3646 Extra Details: NaN3(0.01%) was added in the experiment solute perturbation analysis; Structural stability;,partially folded state

Submission Details

ID: Rib9udm23

Submitter: Connie Wang

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

Version: 1

Publication Details
Ramsay G;Freire E,Biochemistry (1990) Linked thermal and solute perturbation analysis of cooperative domain interactions in proteins. Structural stability of diphtheria toxin. PMID:2271548
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 PDB Entries

Structure ID Release Date Resolution Structure Title
1FWZ 2000-09-25T00:00:00+0000 2.3 GLU20ALA DTXR
1BI0 1998-06-21T00:00:00+0000 2.3 STRUCTURE OF APO-AND HOLO-DIPHTHERIA TOXIN REPRESSOR
1BI3 1998-06-21T00:00:00+0000 2.4 STRUCTURE OF APO-AND HOLO-DIPHTHERIA TOXIN REPRESSOR
1BI2 1998-06-21T00:00:00+0000 2.3 STRUCTURE OF APO-AND HOLO-DIPHTHERIA TOXIN REPRESSOR
1BI1 1998-06-21T00:00:00+0000 2.2 STRUCTURE OF APO-AND HOLO-DIPHTHERIA TOXIN REPRESSOR
1F5T 2000-06-15T00:00:00+0000 3.0 DIPHTHERIA TOX REPRESSOR (C102D MUTANT) COMPLEXED WITH NICKEL AND DTXR CONSENSUS BINDING SEQUENCE
1DPR 1995-02-06T00:00:00+0000 3.0 STRUCTURES OF THE APO-AND METAL ION ACTIVATED FORMS OF THE DIPHTHERIA TOX REPRESSOR FROM CORYNEBACTERIUM DIPHTHERIAE
1BYM 1998-10-17T00:00:00+0000 0 SOLUTION STRUCTURES OF THE C-TERMINAL DOMAIN OF DIPHTHERIA TOXIN REPRESSOR
2TDX 1998-06-22T00:00:00+0000 2.4 DIPHTHERIA TOX REPRESSOR (C102D MUTANT) COMPLEXED WITH NICKEL
1QVP 2003-08-28T00:00:00+0000 0 C terminal SH3-like domain from Diphtheria toxin Repressor residues 144-226.

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
394.8 A,B,C,D Diphtheria toxin repressor P0DJL7 DTXR_CORDI
398.4 A,B,C,D Diphtheria toxin repressor H2I233 DTXR_CORDW