Protein thermostability above 100 degreesC: a key role for ionic interactions.


The discovery of hyperthermophilic microorganisms and the analysis of hyperthermostable enzymes has established the fact that multisubunit enzymes can survive for prolonged periods at temperatures above 100 degreesC. We have carried out homology-based modeling and direct structure comparison on the hexameric glutamate dehydrogenases from the hyperthermophiles Pyrococcus furiosus and Thermococcus litoralis whose optimal growth temperatures are 100 degreesC and 88 degreesC, respectively, to determine key stabilizing features. These enzymes, which are 87% homologous, differ 16-fold in thermal stability at 104 degreesC. We observed that an intersubunit ion-pair network was substantially reduced in the less stable enzyme from T. litoralis, and two residues were then altered to restore these interactions. The single mutations both had adverse effects on the thermostability of the protein. However, with both mutations in place, we observed a fourfold improvement of stability at 104 degreesC over the wild-type enzyme. The catalytic properties of the enzymes were unaffected by the mutations. These results suggest that extensive ion-pair networks may provide a general strategy for manipulating enzyme thermostability of multisubunit enzymes. However, this study emphasizes the importance of the exact local environment of a residue in determining its effects on stability. Study holds ProTherm entries: 3463, 3464, 3465, 3466, 3467 Extra Details: thermostability; ionic interactions; local environment;,glutamate dehydrogenase; hyperthermostable enzymes

Submission Details

ID: 8xX499FG4

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:21 p.m.

Version: 1

Publication Details
Vetriani C;Maeder DL;Tolliday N;Yip KS;Stillman TJ;Britton KL;Rice DW;Klump HH;Robb FT,Proc. Natl. Acad. Sci. U.S.A. (1998) Protein thermostability above 100 degreesC: a key role for ionic interactions. PMID:9770481
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 Glutamate dehydrogenase Q56304 DHE3_THELN
100.0 Glutamate dehydrogenase P80319 DHE3_PYRFU
96.9 Glutamate dehydrogenase Q47950 DHE3_PYRAB
96.0 Glutamate dehydrogenase P0CL73 DHE3_PYRHO
96.0 Glutamate dehydrogenase P0CL72 DHE3_PYRHR
96.0 Glutamate dehydrogenase Q47951 DHE3_PYREN
100.0 Glutamate dehydrogenase Q09115 DHE3_PYRWO