Activity, stability and flexibility in glycosidases adapted to extreme thermal environments.


To elucidate the strategy of low temperature adaptation for a cold-adapted family 8 xylanase, the thermal and chemical stabilities, thermal inactivation, thermodependence of activity and conformational flexibility, as well as the thermodynamic basis of these processes, were compared with those of a thermophilic homolog. Differential scanning calorimetry, fluorescence monitoring of guanidine hydrochloride unfolding and fluorescence quenching were used, among other techniques, to show that the cold-adapted enzyme is characterized by a high activity at low temperatures, a poor stability and a high flexibility. In contrast, the thermophilic enzyme is shown to have a reduced low temperature activity, high stability and a reduced flexibility. These findings agree with the hypothesis that cold-adapted enzymes overcome the quandary imposed by low temperature environments via a global or local increase in the flexibility of their molecular edifice, with this in turn leading to a reduced stability. Analysis of the guanidine hydrochloride unfolding, as well as the thermodynamic parameters of irreversible thermal unfolding and thermal inactivation shows that the driving force for this denaturation and inactivation is a large entropy change while a low enthalpy change is implicated in the low temperature activity. A reduced number of salt-bridges are believed to be responsible for both these effects. Guanidine hydrochloride unfolding studies also indicate that both family 8 enzymes unfold via an intermediate prone to aggregation. Study holds ProTherm entries: 16152, 16153, 16154, 16155, 16156, 16157, 16158, 16159, 16160 Extra Details: i) 500 mM 3-(1-pyridinio)-1-propanesulfonate was added in the experiment.,ii) DSC scan rate 0.2 K/min family 8 glycosyl hydrolases; xylanase; thermodynamics; psychrophiles; thermophiles

Submission Details

ID: qrmojudk3

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:47 p.m.

Version: 1

Publication Details
Collins T;Meuwis MA;Gerday C;Feller G,J. Mol. Biol. (2003) Activity, stability and flexibility in glycosidases adapted to extreme thermal environments. PMID:12691750
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 Cellulose 1,4-beta-cellobiosidase (reducing end) CelS A3DH67 GUNS_CLOTH
100.0 Cellulose 1,4-beta-cellobiosidase (reducing end) CelS P0C2S5 GUNS_CLOTM