Salt bridges are pivotal for the kinetic stability of GH26 endomannanase (ManB-1601).
IR@CFTRI: CSIR-Central Food Technological Research Institute, Mysore
View Archive Info| Field | Value | |
| Relation |
http://ir.cftri.com/14109/
https://dx.doi.org/10.1016/j.ijbiomac.2019.04.175 |
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| Title |
Salt bridges are pivotal for the kinetic stability of GH26 endomannanase
(ManB-1601).
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| Creator |
Gaurav Singh, Kaira
Mukesh, Kapoor Usharani, D. |
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| Subject |
02 Bacteriology
05 Enzymes |
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| Description |
Hitherto, how salt bridges contribute towards the structure-function of endo-mannanases has not
been demonstrated. In the present study, we revealed that ManB-1601 (GH26 endo-mannanase
from Bacillus sp.) has eight salt bridges which are highly conserved among GH26 endomannanases
from Bacillus spp. Disruption of salt bridges do not alter overall structure, optimum
pH and temperature of ManB-1601. Among the salt bridges, elimination of K95/E156 and
E171/R221 pair decreased the substrate affinity and catalytic efficiency of ManB-1601.
Differential scanning calorimetry and isothermal equilibrium denaturation studies suggested that
salt bridges do not markedly contribute towards thermal (ΔTm 0 to -50C) and conformational
stability (ΔΔG -0.37 to -1.25 Kcal mol-1) of ManB-1601. Interestingly, salt bridges were found to
prominently contribute towards kinetic stability of ManB-1601 as salt bridge mutants exhibited
drastic reduction in half-life of enzyme inactivation (T1/2) at 660C (1.1 to 6-fold) and 700C (4.09
to 22.5-fold). Molecular dynamic simulations studies showed that salt bridges contribute towards
maintaining the biological activity against thermal denaturation by rigidifying the active site. Our
study on ManB-1601 suggest that even in the case salt bridges do not confer thermal and
conformational stabilities they may serve as crucial structural elements for enzyme functioning
by contributing towards kinetic stability.
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| Date |
2019
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| Type |
Article
PeerReviewed |
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| Format |
pdf
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| Language |
en
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| Identifier |
http://ir.cftri.com/14109/1/International%20Journal%20of%20Biological%20Macromolecules%202019.pdf
Gaurav Singh, Kaira and Mukesh, Kapoor and Usharani, D. (2019) Salt bridges are pivotal for the kinetic stability of GH26 endomannanase (ManB-1601). International Journal of Biological Macromolecules, 133. pp. 1236-1241. ISSN 0141-8130 |
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