Metal-dependent thermal stability of recombinant endo-mannanase (ManB-1601) belonging to family GH 26 from Bacillus sp. CFR1601

Praveen Kumar, S. and Appu Rao G., G. and Kapoor, Mukesh (2016) Metal-dependent thermal stability of recombinant endo-mannanase (ManB-1601) belonging to family GH 26 from Bacillus sp. CFR1601. Enzyme and Microbial Technology, 84. 41 - 49.

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Official URL: https://doi.org/10.1016/j.enzmictec.2015.12.010

Abstract

A GH 26 endo-mannanase from Bacillus sp. CFR1601 was purified to homogeneity (Mw ∼39kDa, specific activity 10,461.5±100IU/mg). Endo-mannanase gene (manb-1601, 1083bp, accession No. KM404299) was expressed in Escherichia coli BL21 (DE3) and showed typical fingerprints of α/β proteins in the far-UV CD. A high degree of conservation among amino acid residues involved in metal chelation (His-1, 23 and Glu-336) and internal repeats (122–152 and 181–212) was observed in endo-mannanases reported from various Bacillus sp. Thermal inactivation kinetics suggested that metal ions are quintessential for stabilization of ManB-1601 structure as holoenzyme (Ea 87.4kcal/mol, ΔH 86.7kcal/mol, ΔS 186.6cal/k/mol) displayed better values of thermodynamic parameters compared to metal-depleted ManB-1601 (Ea 47kcal/mol, ΔH 45.7kcal/mol, ΔS 64.7cal/k/mol). EDTA treatment of ManB-1601 not only lead to transitions in both secondary and tertiary structure but also promulgated the population of conformational state that unfolds at lower temperature. ManB-1601 followed a three-state process for thermal inactivation wherein loss of tertiary structure preceded the concurrent loss of secondary structure and activity.

Item Type: Article
Uncontrolled Keywords: Endo-mannanase, sp., Thermal stability, Metal-binding site, GH family 26
Subjects: C Chemical Science > Biochemistry
Divisions: Department of > Biochemistry
Depositing User: manjula User
Date Deposited: 24 Jun 2019 10:04
Last Modified: 24 Jun 2019 10:04
URI: http://eprints.uni-mysore.ac.in/id/eprint/3662

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