Differential scanning calorimetry of the irreversible denaturation of Escherichia coli glucosamine-6-phosphate deaminase.


Abstract

The thermal denaturation of Escherichia coli glucosamine-6-phosphate deaminase (G6PD) at neutral pH was studied by means of differential scanning calorimetry (DSC). In the concentration range 0.6-7.3 mg mL-1, the denaturation of this hexameric enzyme was completely irreversible as judged by the absence of any endotherm on rescanning of previously scanned samples. However, the study of the effect of scanning rate on DSC curves indicated that the denaturation of G6PD is, most likely, a complex process which includes transitions in equilibrium as well as an irreversible step; in addition, it was found that application of the equilibrium formalism to the analysis of calorimetric data seems to be justified in this case, provided that scanning rates used are above 0.75 K min-1. The calorimetric and van't Hoff enthalpies for G6PD were 1260 +/- 118 and 160 +/- 27 kcal mol-1, respectively, indicating the presence of intermediates in the process. Accordingly, the DSC curves were adequately fitted to a model including six two-state sequential transitions. The observed protein-concentration dependence of the temperature at the maximum heat capacity, Tm, for each of the individual transitions suggests that G6PD dissociates to dimers in two consecutive steps. Using a model that includes dissociation explicitly, we calculated the thermodynamic parameters for each step. From this data, the enthalpy and free energy for the disruption of one dimer-dimer contact were roughly estimated, at pH 7.1 and 51 degrees C, as 57 and 2.1 kcal mol-1, respectively. Study holds ProTherm entries: 4547 Extra Details: glucosamine-6-phosphate deaminase; hexameric enzyme; endotherm;,scanning rate; intermediates; thermodynamic parameters

Submission Details

ID: BGG9Dd2T

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:26 p.m.

Version: 1

Publication Details
Hernández-Arana A;Rojo-Domínguez A;Altamirano MM;Calcagno ML,Biochemistry (1993) Differential scanning calorimetry of the irreversible denaturation of Escherichia coli glucosamine-6-phosphate deaminase. PMID:8466906
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
1FS5 2002-01-04 1.73 A DISCOVERY OF THREE ALTERNATE CONFORMATIONS IN THE ACTIVE SITE OF GLUCOSAMINE-6-PHOSPHATE ISOMERASE
1FSF 2002-01-04 1.9 GLUCOSAMINE-6-PHOSPHATE DEAMINASE FROM E.COLI, T CONFORMER, AT 1.9A RESOLUTION
1JT9 2002-02-20 2.06 Structure of the mutant F174A T form of the Glucosamine-6-Phosphate deaminase from E.coli
1DEA 1996-01-29 2.1 STRUCTURE AND CATALYTIC MECHANISM OF GLUCOSAMINE 6-PHOSPHATE DEAMINASE FROM ESCHERICHIA COLI AT 2.1 ANGSTROMS RESOLUTION
2WU1 2009-10-06 2.2 Glucosamine-6-Phosphate Deaminase Complexed with the Allosteric Activator N-Acetyl-Glucoamine-6-Phosphate both in the Active and Allosteric sites.
1FRZ 2002-01-04 2.2 GLUCOSAMINE-6-PHOSPHATE DEAMINASE FROM E.COLI, R CONFORMER. COMPLEXED WITH THE ALLOSTERIC ACTIVATOR N-ACETYL-GLUCOSAMINE-6-PHOSPHATE AT 2.2 A RESOLUTION
1FS6 2002-01-04 2.2 GLUCOSAMINE-6-PHOSPHATE DEAMINASE FROM E.COLI, T CONFORMER, AT 2.2A RESOLUTION
1FQO 2002-01-04 2.2 GLUCOSAMINE 6-PHOSPHATE DEAMINASE COMPLEXED WITH THE SUBSTRATE OF THE REVERSE REACTION FRUCTOSE 6-PHOSPHATE (OPEN FORM)
1CD5 2000-03-06 2.3 GLUCOSAMINE-6-PHOSPHATE DEAMINASE FROM E.COLI, T CONFORMER
1HOR 1996-01-29 2.4 STRUCTURE AND CATALYTIC MECHANISM OF GLUCOSAMINE 6-PHOSPHATE DEAMINASE FROM ESCHERICHIA COLI AT 2.1 ANGSTROMS RESOLUTION
1HOT 1996-04-03 2.4 GLUCOSAMINE 6-PHOSPHATE DEAMINASE COMPLEXED WITH THE ALLOSTERIC ACTIVATOR N-ACETYL-GLUCOSAMINE-6-PHOSPHATE

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
94.4 Glucosamine-6-phosphate deaminase A4W844 NAGB_ENT38
94.4 Glucosamine-6-phosphate deaminase A6T6C1 NAGB_KLEP7
94.7 Glucosamine-6-phosphate deaminase B5XZG9 NAGB_KLEP3
95.1 Glucosamine-6-phosphate deaminase Q8Z8G0 NAGB_SALTI
95.5 Glucosamine-6-phosphate deaminase A8AJE0 NAGB_CITK8
95.5 Glucosamine-6-phosphate deaminase Q8ZQX7 NAGB_SALTY
95.5 Glucosamine-6-phosphate deaminase B4TPZ8 NAGB_SALSV
95.5 Glucosamine-6-phosphate deaminase B5BCC5 NAGB_SALPK
95.5 Glucosamine-6-phosphate deaminase C0PWA5 NAGB_SALPC
95.5 Glucosamine-6-phosphate deaminase A9MUG8 NAGB_SALPB
95.5 Glucosamine-6-phosphate deaminase Q5PCH6 NAGB_SALPA
95.5 Glucosamine-6-phosphate deaminase B4SYN7 NAGB_SALNS
95.5 Glucosamine-6-phosphate deaminase B4TB82 NAGB_SALHS
95.5 Glucosamine-6-phosphate deaminase B5R824 NAGB_SALG2
95.5 Glucosamine-6-phosphate deaminase B5QWC8 NAGB_SALEP
95.5 Glucosamine-6-phosphate deaminase B5FNB9 NAGB_SALDC
95.5 Glucosamine-6-phosphate deaminase Q57RQ0 NAGB_SALCH
95.5 Glucosamine-6-phosphate deaminase B5EZC1 NAGB_SALA4
95.5 Glucosamine-6-phosphate deaminase A9MKA9 NAGB_SALAR
98.9 Glucosamine-6-phosphate deaminase Q32IQ2 NAGB_SHIDS
99.6 Glucosamine-6-phosphate deaminase Q8FJX7 NAGB_ECOL6
99.6 Glucosamine-6-phosphate deaminase P59688 NAGB_SHIFL
99.6 Glucosamine-6-phosphate deaminase Q0T6S6 NAGB_SHIF8
100.0 Glucosamine-6-phosphate deaminase Q3Z4C2 NAGB_SHISS
100.0 Glucosamine-6-phosphate deaminase Q324M6 NAGB_SHIBS
100.0 Glucosamine-6-phosphate deaminase B2TU53 NAGB_SHIB3
100.0 Glucosamine-6-phosphate deaminase B7LKT5 NAGB_ESCF3
100.0 Glucosamine-6-phosphate deaminase Q1REP9 NAGB_ECOUT
100.0 Glucosamine-6-phosphate deaminase B1LLC0 NAGB_ECOSM
100.0 Glucosamine-6-phosphate deaminase B6HYN6 NAGB_ECOSE
100.0 Glucosamine-6-phosphate deaminase B7N9S4 NAGB_ECOLU
100.0 Glucosamine-6-phosphate deaminase P0A759 NAGB_ECOLI
100.0 Glucosamine-6-phosphate deaminase B1IY50 NAGB_ECOLC
100.0 Glucosamine-6-phosphate deaminase Q0TK13 NAGB_ECOL5
100.0 Glucosamine-6-phosphate deaminase A1A8T7 NAGB_ECOK1
100.0 Glucosamine-6-phosphate deaminase A7ZXT7 NAGB_ECOHS
100.0 Glucosamine-6-phosphate deaminase B1X6L1 NAGB_ECODH
100.0 Glucosamine-6-phosphate deaminase C4ZWF4 NAGB_ECOBW
100.0 Glucosamine-6-phosphate deaminase B7M5J6 NAGB_ECO8A
100.0 Glucosamine-6-phosphate deaminase B7MPI3 NAGB_ECO81
100.0 Glucosamine-6-phosphate deaminase B7NMM9 NAGB_ECO7I
100.0 Glucosamine-6-phosphate deaminase B5YQM0 NAGB_ECO5E
100.0 Glucosamine-6-phosphate deaminase P0A760 NAGB_ECO57
100.0 Glucosamine-6-phosphate deaminase B7L9L4 NAGB_ECO55
100.0 Glucosamine-6-phosphate deaminase B7MFT4 NAGB_ECO45
100.0 Glucosamine-6-phosphate deaminase B7UKV0 NAGB_ECO27
100.0 Glucosamine-6-phosphate deaminase A7ZJ60 NAGB_ECO24