The introduction of disulfide bonds has been used as a strategy to enhance the stability of Bacillus circulans xylanase. The transition temperature of the S100C/N148C (DS1), V98C/A152C (DS2), and A1GC/G187,C188 (cXl) in comparison to the wild type was increased by 5.0, 4.1 and 3.8 degrees C, respectively. Interestingly, a combination of two disulfide bonds of DS1 and cXl (cDS1, circular disulfide 1) led to a 12 degrees C increase in the transition temperature. Importantly, an increase in the melting point and DeltaDeltaG values of the cDS1 mutant was cooperative. These results suggest that the mechanism of stabilization by disulfide bonds under irreversible denaturation condition is achieved through: (1) a change in the rate-limiting step on the denaturation pathway; (2) destabilizing the unfolded state without affecting the relative rate constants on the denaturation pathway (like cXl mutant); and (3) or combination of the two (cDS1 mutant). Study holds ProTherm entries: 22319, 22320, 22321, 22322, 22323, 22324, 22325, 22326, 22327, 22328, 22329, 22330, 22331, 22332, 22333, 22334, 22335, 22336, 22337, 22338, 22339, 22340, 22341, 22342, 22343, 22344 Extra Details: data were obtained with the scanning rate of 57 degrees/h Xylanase; Stabilization; Disulfide bond
Submitter: Connie Wang
Submission Date: April 24, 2018, 8:53 p.m.
|Number of data points||59|
|Proteins||Endo-1,4-beta-xylanase ; Endo-1,4-beta-xylanase|
|Assays/Quantities/Protocols||Experimental Assay: Cm ; Experimental Assay: m ; Experimental Assay: dG_H2O ; Experimental Assay: dCp temp:51.2 C ; Experimental Assay: ddG ; Experimental Assay: dCp ; Experimental Assay: dHcal ; Experimental Assay: activity ; Experimental Assay: Tm ; Derived Quantity: ddG_H2O ; Derived Quantity: dTm|
|Libraries||Mutations for sequence ASTDYWQNWTDGGGIVNAVNGSGGNYSVNWSNTGNFVVGKGWTTGSPFRTINYNAGVWAPNGNGYLTLYGWTRSPLIEYYVVDSWGTYRPTGTYKGTVKSDGGTYDIYTTTRYNAPSIDGDRTTFTQYWSVRQSKRPTGSNATITFTNHVNAWKSHGMNLGSNWAYQVMATCGYQSSGSSNVTVW|