Truncation of C-terminal amino acids of GH26 endo-mannanase (ManB-1601) affects biochemical properties and stability against anionic surfactants

Monica, P. and Sarma, Mutturi and Mukesh, Kapoor (2022) Truncation of C-terminal amino acids of GH26 endo-mannanase (ManB-1601) affects biochemical properties and stability against anionic surfactants. Enzyme and Microbial Technology, 157. pp. 1-15.

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Abstract

Hitherto, the contribution of C-terminal amino acids in structure, stability and function of GH26 endo-mannanases has not been demonstrated. Semi-logarithmic plot of endo-mannanase activity showed a progressive decline with increase in the number of truncated amino acids [ManB-CΔ5 (129 U/mL), ManB-CΔ10 (47 U/mL), ManB-CΔ15 (0.05 U/mL) and ManB-CΔ20 (0.02 U/mL)]. ManB-CΔ5 and ManB-CΔ10 exhibited similar temperature and pH optima and product profile but biochemical properties (kinetic constants, mannan hydro lysis, response to metal ions and enzyme inhibitors) and stability (in presence of commercial detergents, anionic surfactants and organic solvents and half-life) were markedly affected. Interaction of truncated proteins with anionic surfactants was probed using intrinsic, Nile red, acrylamide quenching, resonance light scattering and synchronous fluorescence spectroscopy studies. Truncation of ten amino acids increased vulnerability to anionic surfactants as conformational changes, exposure of the hydrophobic core and susceptibility to unfolding process were observed. The microenvironment around Trp residues was affected more with surfactants as compared to Tyr residues in truncated proteins. Zn2+ coordination might not play a role in providing stability against SDS. MD simulation studies corroborated that C-terminal amino acids (327− 336) helps in structure stabilization, regulating flexibility of loops around the active site and preventing denaturation in the presence of SDS.

Item Type:	Article
Uncontrolled Keywords:	GH26 endo-mannanase, C-terminal amino acids, Surfactants Enzyme stability, Molecular dynamics
Subjects:	600 Technology > 08 Food technology > 16 Nutritive value > 02 Amino acids 600 Technology > 08 Food technology > 16 Nutritive value > 05 Enzymes
Divisions:	Protein Chemistry and Technology
Depositing User:	Somashekar K S
Date Deposited:	05 Mar 2025 10:07
Last Modified:	05 Mar 2025 10:07
URI:	http://ir.cftri.res.in/id/eprint/19178

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