Differential scanning calorimetry study of reversible, partial unfolding transitions in dodecameric glutamine synthetase from Escherichia coli.


Abstract

Partial unfolding of dodecameric glutamine synthetase (GS) from Escherichia coli has been studied by differential scanning calorimetry (DSC). A single endotherm (tm = 51.6 +/- 0.1 degrees C and delta Hcal = 211 +/- 4 kcal/mol of enzyme) was observed in DSC experiments with Mn.GS in the presence of 1.0 mM free Mn2+ and 100 mM KCl at pH 7. The dodecameric structure of Mn.GS was retained throughout heating cycles, and thermal transitions were reversible as shown by rescans [with 6-18 mg of GS (Mr 622,000) from 15 to 68 degrees C at 20-60 degrees C/h] and by greater than 93% recovery of activity. A cooperative ratio delta Hcal/delta HvH of 1.6 +/- 0.1 and deconvolution analysis show two cooperative units (two-state transitions): t1 = 50.4 and t2 = 51.7 degrees C; the ratio of the relative sizes of thermally labile domains is approximately 1:2 as judged by delta H2/delta H1 approximately equal to 2. However, the thermally induced overall enthalpy change (0.34 cal/g) for GS dodecamer is only 5-10% of that for thermal unfolding of small globular proteins at 50 degrees C. The t1 and t2 values from deconvolutions of DSC data agree with t0.5 values previously calculated from spectral measurements of temperature-induced exposures of approximately 0.7 of 2 Trp and approximately 2 of 17 Tyr per subunit, respectively [Shrake et al. (1989) Biochemistry 28, 6281-6294], over a 14 degrees C temperature range using both stabilizing and destabilizing conditions for Mn.GS.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 4381 Extra Details: endotherm; activity; cooperative units;,partial unfolding reactions

Submission Details

ID: o9pYUEv64

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:25 p.m.

Version: 1

Publication Details
Ginsburg A;Zolkiewski M,Biochemistry (1991) Differential scanning calorimetry study of reversible, partial unfolding transitions in dodecameric glutamine synthetase from Escherichia coli. PMID:1680002
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
1F52 2000-06-28 2.49 CRYSTAL STRUCTURE OF GLUTAMINE SYNTHETASE FROM SALMONELLA TYPHIMURIUM CO-CRYSTALLIZED WITH ADP
1F1H 2001-04-04 2.67 CRYSTAL STRUCTURE OF GLUTAMINE SYNTHETASE FROM SALMONELLA TYPHIMURIUM WITH THALLIUM IONS
1LGR 1994-11-30 2.79 INTERACTIONS OF NUCLEOTIDES WITH FULLY UNADENYLYLATED GLUTAMINE SYNTHETASE FROM SALMONELLA TYPHIMURIUM
2LGS 1994-11-30 2.8 FEEDBACK INHIBITION OF FULLY UNADENYLYLATED GLUTAMINE SYNTHETASE FROM SALMONELLA TYPHIMURIUM BY GLYCINE, ALANINE, AND SERINE
1FPY 2001-04-04 2.89 CRYSTAL STRUCTURE OF GLUTAMINE SYNTHETASE FROM SALMONELLA TYPHIMURIUM WITH INHIBITOR PHOSPHINOTHRICIN
2GLS 1989-10-15 3.5 REFINED ATOMIC MODEL OF GLUTAMINE SYNTHETASE AT 3.5 ANGSTROMS RESOLUTION
5LDF 2016-08-10 6.2 Maltose binding protein genetically fused to dodecameric glutamine synthetase

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
98.1 Glutamine synthetase P0A1P6 GLN1B_SALTY
98.1 Glutamine synthetase P0A1P7 GLN1B_SALTI
100.0 Glutamine synthetase P0A9C8 GLN1B_SHIFL
100.0 Glutamine synthetase P0A9C5 GLN1B_ECOLI
100.0 Glutamine synthetase P0A9C6 GLN1B_ECOL6
100.0 Glutamine synthetase P0A9C7 GLN1B_ECO57