Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase

Søs Terpenholt, Leonardo De Maria, Mats H.M. Olsson, Lars H. Christensen, Michael Skjøt, Peter Westh, Jan H. Jensen, Leila Lo Leggio

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

New variants of β-1,4-galactanase from the mesophilic organism Aspergillus aculeatus were designed using the structure of β-1,4-galactanase from the thermophile organism Myceliophthora thermophila as a template. Some of the variants were generated using PROPKA 3.0, a validated pKa prediction tool, to test its usefulness as an enzyme design tool. The PROPKA designed variants were D182N and S185D/Q188T, G104D/A156R. Variants Y295F and G306A were designed by a consensus approach, as a complementary and validated design method. D58N was a stabilizing mutation predicted by both methods. The predictions were experimentally validated by measurements of the melting temperature (Tm) by differential scanning calorimetry. We found that the Tm is elevated by 1.1 °C for G306A, slightly increased (in the range of 0.34 to 0.65 °C) for D182N, D58N, Y295F and unchanged or decreased for S185D/Q188T and G104D/A156R. The Tm changes were in the range predicted by PROPKA. Given the experimental errors, only the D58N and G306A show significant increase in thermodynamic stability.

Given the practical importance of kinetic stability, the kinetics of the irreversible enzyme inactivation process were also investigated for the wild-type and three variants and found to be biphasic. The half-lives of thermal inactivation were approximately doubled in G306A, unchanged for D182N and, disappointingly, a lot lower for D58N. In conclusion, this study tests a new method for estimating Tm changes for mutants, adds to the available data on the effect of substitutions on protein thermostability and identifies an interesting thermostabilizing mutation, which may be beneficial also in other galactanases.
OriginalsprogEngelsk
TidsskriftComputational and Structural Biotechnology Journal
Vol/bind2015
Udgave nummer13
Sider (fra-til)256-264
ISSN2001-0370
DOI
StatusUdgivet - 2015

Citer dette

Terpenholt, S., De Maria, L., Olsson, M. H. M., Christensen, L. H., Skjøt, M., Westh, P., ... Lo Leggio, L. (2015). Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase. Computational and Structural Biotechnology Journal, 2015(13), 256-264. https://doi.org/10.1016/j.csbj.2015.03.010
Terpenholt, Søs ; De Maria, Leonardo ; Olsson, Mats H.M. ; Christensen, Lars H. ; Skjøt, Michael ; Westh, Peter ; Jensen, Jan H. ; Lo Leggio, Leila. / Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase. I: Computational and Structural Biotechnology Journal. 2015 ; Bind 2015, Nr. 13. s. 256-264.
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title = "Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase",
abstract = "New variants of β-1,4-galactanase from the mesophilic organism Aspergillus aculeatus were designed using the structure of β-1,4-galactanase from the thermophile organism Myceliophthora thermophila as a template. Some of the variants were generated using PROPKA 3.0, a validated pKa prediction tool, to test its usefulness as an enzyme design tool. The PROPKA designed variants were D182N and S185D/Q188T, G104D/A156R. Variants Y295F and G306A were designed by a consensus approach, as a complementary and validated design method. D58N was a stabilizing mutation predicted by both methods. The predictions were experimentally validated by measurements of the melting temperature (Tm) by differential scanning calorimetry. We found that the Tm is elevated by 1.1 °C for G306A, slightly increased (in the range of 0.34 to 0.65 °C) for D182N, D58N, Y295F and unchanged or decreased for S185D/Q188T and G104D/A156R. The Tm changes were in the range predicted by PROPKA. Given the experimental errors, only the D58N and G306A show significant increase in thermodynamic stability.Given the practical importance of kinetic stability, the kinetics of the irreversible enzyme inactivation process were also investigated for the wild-type and three variants and found to be biphasic. The half-lives of thermal inactivation were approximately doubled in G306A, unchanged for D182N and, disappointingly, a lot lower for D58N. In conclusion, this study tests a new method for estimating Tm changes for mutants, adds to the available data on the effect of substitutions on protein thermostability and identifies an interesting thermostabilizing mutation, which may be beneficial also in other galactanases.",
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Terpenholt, S, De Maria, L, Olsson, MHM, Christensen, LH, Skjøt, M, Westh, P, Jensen, JH & Lo Leggio, L 2015, 'Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase' Computational and Structural Biotechnology Journal, bind 2015, nr. 13, s. 256-264. https://doi.org/10.1016/j.csbj.2015.03.010

Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase. / Terpenholt, Søs; De Maria, Leonardo; Olsson, Mats H.M.; Christensen, Lars H.; Skjøt, Michael; Westh, Peter; Jensen, Jan H.; Lo Leggio, Leila.

I: Computational and Structural Biotechnology Journal, Bind 2015, Nr. 13, 2015, s. 256-264.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Effect of mutations on the thermostability of Aspergillus aculeatus β-1, 4-galactanase

AU - Terpenholt, Søs

AU - De Maria, Leonardo

AU - Olsson, Mats H.M.

AU - Christensen, Lars H.

AU - Skjøt, Michael

AU - Westh, Peter

AU - Jensen, Jan H.

AU - Lo Leggio, Leila

PY - 2015

Y1 - 2015

N2 - New variants of β-1,4-galactanase from the mesophilic organism Aspergillus aculeatus were designed using the structure of β-1,4-galactanase from the thermophile organism Myceliophthora thermophila as a template. Some of the variants were generated using PROPKA 3.0, a validated pKa prediction tool, to test its usefulness as an enzyme design tool. The PROPKA designed variants were D182N and S185D/Q188T, G104D/A156R. Variants Y295F and G306A were designed by a consensus approach, as a complementary and validated design method. D58N was a stabilizing mutation predicted by both methods. The predictions were experimentally validated by measurements of the melting temperature (Tm) by differential scanning calorimetry. We found that the Tm is elevated by 1.1 °C for G306A, slightly increased (in the range of 0.34 to 0.65 °C) for D182N, D58N, Y295F and unchanged or decreased for S185D/Q188T and G104D/A156R. The Tm changes were in the range predicted by PROPKA. Given the experimental errors, only the D58N and G306A show significant increase in thermodynamic stability.Given the practical importance of kinetic stability, the kinetics of the irreversible enzyme inactivation process were also investigated for the wild-type and three variants and found to be biphasic. The half-lives of thermal inactivation were approximately doubled in G306A, unchanged for D182N and, disappointingly, a lot lower for D58N. In conclusion, this study tests a new method for estimating Tm changes for mutants, adds to the available data on the effect of substitutions on protein thermostability and identifies an interesting thermostabilizing mutation, which may be beneficial also in other galactanases.

AB - New variants of β-1,4-galactanase from the mesophilic organism Aspergillus aculeatus were designed using the structure of β-1,4-galactanase from the thermophile organism Myceliophthora thermophila as a template. Some of the variants were generated using PROPKA 3.0, a validated pKa prediction tool, to test its usefulness as an enzyme design tool. The PROPKA designed variants were D182N and S185D/Q188T, G104D/A156R. Variants Y295F and G306A were designed by a consensus approach, as a complementary and validated design method. D58N was a stabilizing mutation predicted by both methods. The predictions were experimentally validated by measurements of the melting temperature (Tm) by differential scanning calorimetry. We found that the Tm is elevated by 1.1 °C for G306A, slightly increased (in the range of 0.34 to 0.65 °C) for D182N, D58N, Y295F and unchanged or decreased for S185D/Q188T and G104D/A156R. The Tm changes were in the range predicted by PROPKA. Given the experimental errors, only the D58N and G306A show significant increase in thermodynamic stability.Given the practical importance of kinetic stability, the kinetics of the irreversible enzyme inactivation process were also investigated for the wild-type and three variants and found to be biphasic. The half-lives of thermal inactivation were approximately doubled in G306A, unchanged for D182N and, disappointingly, a lot lower for D58N. In conclusion, this study tests a new method for estimating Tm changes for mutants, adds to the available data on the effect of substitutions on protein thermostability and identifies an interesting thermostabilizing mutation, which may be beneficial also in other galactanases.

U2 - 10.1016/j.csbj.2015.03.010

DO - 10.1016/j.csbj.2015.03.010

M3 - Journal article

VL - 2015

SP - 256

EP - 264

JO - Computational and Structural Biotechnology Journal

JF - Computational and Structural Biotechnology Journal

SN - 2001-0370

IS - 13

ER -