Thermodynamics of the binding of L-arabinose and of D-galactose to the L-arabinose-binding protein of Escherichia coli.

Abstract

The thermodynamics of the binding of L-arabinose and of D-galactose to the L-arabinose-binding protein of Escherichia coli have been studied by isothermal and scanning calorimetry. The binding reaction with arabinose is characterized by an enthalpy change of -15.3 +/- 0.5 kcal mol-1 at 25 degrees C, and a large decrease in apparent heat capacity, amounting to -0.44 +/- 0.05 kcal K-1 mol-1, which is constant over the temperature range 8 to 30 degrees C. Very similar results were obtained with D-galactose. These calorimetric results have been combined with binding constants determined by equilibrium dialysis (Clark, A. F., Gerken, T. A., and Hogg, R. W. (1982) Biochemistry 21, 2227-2233) to obtain free energy and entropy changes over the range 5 to 30 degrees C, and by extrapolation to 60 degrees C. The protein undergoes reversible unfolding on being heated with an increase in enthalpy at 53.5 degrees C of 151.8 +/- 1.1 kcal mol-1 (169.2 +/- 1.2 kcal mol-1 at 59.0 degrees C) and in apparent heat capacity of 3.16 +/- 0.07 kcal K-1 mol-1. In the presence of arabinose, the unfolding enthalpy is increased to 200.7 +/- 1.8 kcal mol-1 at 59.0 degrees C, the increase being due to the enthalpy of dissociation of the ligand which amounts to 31 kcal mol-1 at the unfolding temperature. The unfolding temperature is increased by the presence of excess arabinose or galactose, an effect which is due solely to displacement by the added ligand of the unfolding-dissociation equilibrium. The thermodynamic data are discussed in connection with the detailed structural information available for this system from x-ray crystallography (Newcomer, M. E., Gilliland, G. L. and Quiocho, F. A. (1981) J. Biol. Chem. 256, 13213-13217, and references cited therein). Study holds ProTherm entries: 2994 Extra Details: additive : EDTA(1 mM), thermodynamics; enthalpy change; heat capacity; free energy;,entropy change; L-arabinose-binding protein

Submission Details

ID: Hm2hVTbQ3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:20 p.m.

Version: 1

Publication Details
Fukada H;Sturtevant JM;Quiocho FA,J. Biol. Chem. (1983) Thermodynamics of the binding of L-arabinose and of D-galactose to the L-arabinose-binding protein of Escherichia coli. PMID:6355105
Additional Information

Study Summary

Number of data points 3
Proteins L-arabinose-binding periplasmic protein ; L-arabinose-binding periplasmic protein
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: dCp ; Experimental Assay: dHcal ; Experimental Assay: Tm
Libraries Mutations for sequence ENLKLGFLVKQPEEPWFQTEWKFADKAGKDLGFEVIKIAVPDGEKTLNAIDSLAASGAKGFVICTPDPKLGSAIVAKARGYDMKVIAVDDQFVNAKGKPMDTVPLVMMAATKIGERQGQELYKEMQKRGWDVKESAVMAITANELDTARRRTTGSMDALKAAGFPEKQIYQVPTKSNDIPGAFDAANSMLVQHPEVKHWLIVGMNDSTVLGGVRATEGQGFKAADIIGIGINGVDAVSELSKAQATGFYGSLLPSPDVHGYKSSEMLYNWVAKDVEPPKFTEVTDVVLITRDNFKEELEKKGLGGK

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
8ABP 1991-10-15 1.49 SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES OF AN ARABINOSE-BINDING PROTEIN MUTANT (MET108LEU) WHICH EXHIBITS ENHANCED AFFINITY AND ALTERED SPECIFICITY
7ABP 1991-10-15 1.67 SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES OF AN ARABINOSE-BINDING PROTEIN MUTANT (MET108LEU) WHICH EXHIBITS ENHANCED AFFINITY AND ALTERED SPECIFICITY
6ABP 1991-10-31 1.67 SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES OF AN ARABINOSE-BINDING PROTEIN MUTANT (MET108LEU) WHICH EXHIBITS ENHANCED AFFINITY AND ALTERED SPECIFICITY
1ABE 1993-10-31 1.7 NOVEL STEREOSPECIFICITY OF THE L-ARABINOSE-BINDING PROTEIN
1BAP 1992-01-15 1.75 A PRO TO GLY MUTATION IN THE HINGE OF THE ARABINOSE-BINDING PROTEIN ENHANCES BINDING AND ALTERS SPECIFICITY: SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES
1APB 1992-01-15 1.76 A PRO TO GLY MUTATION IN THE HINGE OF THE ARABINOSE-BINDING PROTEIN ENHANCES BINDING AND ALTERS SPECIFICITY: SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES
5ABP 1992-10-15 1.8 SUBSTRATE SPECIFICITY AND AFFINITY OF A PROTEIN MODULATED BY BOUND WATER MOLECULES
1ABF 1993-10-31 1.9 SUBSTRATE SPECIFICITY AND AFFINITY OF A PROTEIN MODULATED BY BOUND WATER MOLECULES
9ABP 1992-01-15 1.97 A PRO TO GLY MUTATION IN THE HINGE OF THE ARABINOSE-BINDING PROTEIN ENHANCES BINDING AND ALTERS SPECIFICITY: SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES
2WRZ 2009-10-13 2.2 Crystal structure of an arabinose binding protein with designed serotonin binding site in open, ligand-free state

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 L-arabinose-binding periplasmic protein P02924 ARAF_ECOLI