Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity
ABSTRACT The α-amylases are endo-acting enzymes that hydrolyze starch by randomly cleaving the 1,4-α- d -glucosidic linkages between the adjacent glucose units in a linear amylose chain. They have significant advantages in a wide range of applications, particularly in the food industry. The eukaryot...
Published in: | Applied and Environmental Microbiology |
---|---|
Main Authors: | , , , , , |
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Society for Microbiology
2017
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1128/aem.00449-17 https://journals.asm.org/doi/pdf/10.1128/AEM.00449-17 |
id |
crasmicro:10.1128/aem.00449-17 |
---|---|
record_format |
openpolar |
spelling |
crasmicro:10.1128/aem.00449-17 2024-05-12T07:56:29+00:00 Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity Yang, Guang Yao, Hua Mozzicafreddo, Matteo Ballarini, Patrizia Pucciarelli, Sandra Miceli, Cristina Kelly, Robert M. 2017 http://dx.doi.org/10.1128/aem.00449-17 https://journals.asm.org/doi/pdf/10.1128/AEM.00449-17 en eng American Society for Microbiology http://creativecommons.org/licenses/by/4.0/ https://journals.asm.org/non-commercial-tdm-license Applied and Environmental Microbiology volume 83, issue 13 ISSN 0099-2240 1098-5336 Ecology Applied Microbiology and Biotechnology Food Science Biotechnology journal-article 2017 crasmicro https://doi.org/10.1128/aem.00449-17 2024-04-18T06:52:32Z ABSTRACT The α-amylases are endo-acting enzymes that hydrolyze starch by randomly cleaving the 1,4-α- d -glucosidic linkages between the adjacent glucose units in a linear amylose chain. They have significant advantages in a wide range of applications, particularly in the food industry. The eukaryotic α-amylase isolated from the Antarctic ciliated protozoon Euplotes focardii ( Ef Amy) is an alkaline enzyme, different from most of the α-amylases characterized so far. Furthermore, Ef Amy has the characteristics of a psychrophilic α-amylase, such as the highest hydrolytic activity at a low temperature and high thermolability, which is the major drawback of cold-active enzymes in industrial applications. In this work, we applied site-directed mutagenesis combined with rational design to generate a cold-active Ef Amy with improved thermostability and catalytic efficiency at low temperatures. We engineered two Ef Amy mutants. In one mutant, we introduced Pro residues on the A and B domains in surface loops. In the second mutant, we changed Val residues to Thr close to the catalytic site. The aim of these substitutions was to rigidify the molecular structure of the enzyme. Furthermore, we also analyzed mutants containing these combined substitutions. Biochemical enzymatic assays of engineered versions of Ef Amy revealed that the combination of mutations at the surface loops increased the thermostability and catalytic efficiency of the enzyme. The possible mechanisms responsible for the changes in the biochemical properties are discussed by analyzing the three-dimensional structural model. IMPORTANCE Cold-adapted enzymes have high specific activity at low and moderate temperatures, a property that can be extremely useful in various applications as it implies a reduction in energy consumption during the catalyzed reaction. However, the concurrent high thermolability of cold-adapted enzymes often limits their applications in industrial processes. The α-amylase from the psychrophilic Antarctic ciliate Euplotes focardii ... Article in Journal/Newspaper Antarc* Antarctic ASM Journals (American Society for Microbiology) Antarctic The Antarctic Applied and Environmental Microbiology 83 13 |
institution |
Open Polar |
collection |
ASM Journals (American Society for Microbiology) |
op_collection_id |
crasmicro |
language |
English |
topic |
Ecology Applied Microbiology and Biotechnology Food Science Biotechnology |
spellingShingle |
Ecology Applied Microbiology and Biotechnology Food Science Biotechnology Yang, Guang Yao, Hua Mozzicafreddo, Matteo Ballarini, Patrizia Pucciarelli, Sandra Miceli, Cristina Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
topic_facet |
Ecology Applied Microbiology and Biotechnology Food Science Biotechnology |
description |
ABSTRACT The α-amylases are endo-acting enzymes that hydrolyze starch by randomly cleaving the 1,4-α- d -glucosidic linkages between the adjacent glucose units in a linear amylose chain. They have significant advantages in a wide range of applications, particularly in the food industry. The eukaryotic α-amylase isolated from the Antarctic ciliated protozoon Euplotes focardii ( Ef Amy) is an alkaline enzyme, different from most of the α-amylases characterized so far. Furthermore, Ef Amy has the characteristics of a psychrophilic α-amylase, such as the highest hydrolytic activity at a low temperature and high thermolability, which is the major drawback of cold-active enzymes in industrial applications. In this work, we applied site-directed mutagenesis combined with rational design to generate a cold-active Ef Amy with improved thermostability and catalytic efficiency at low temperatures. We engineered two Ef Amy mutants. In one mutant, we introduced Pro residues on the A and B domains in surface loops. In the second mutant, we changed Val residues to Thr close to the catalytic site. The aim of these substitutions was to rigidify the molecular structure of the enzyme. Furthermore, we also analyzed mutants containing these combined substitutions. Biochemical enzymatic assays of engineered versions of Ef Amy revealed that the combination of mutations at the surface loops increased the thermostability and catalytic efficiency of the enzyme. The possible mechanisms responsible for the changes in the biochemical properties are discussed by analyzing the three-dimensional structural model. IMPORTANCE Cold-adapted enzymes have high specific activity at low and moderate temperatures, a property that can be extremely useful in various applications as it implies a reduction in energy consumption during the catalyzed reaction. However, the concurrent high thermolability of cold-adapted enzymes often limits their applications in industrial processes. The α-amylase from the psychrophilic Antarctic ciliate Euplotes focardii ... |
author2 |
Kelly, Robert M. |
format |
Article in Journal/Newspaper |
author |
Yang, Guang Yao, Hua Mozzicafreddo, Matteo Ballarini, Patrizia Pucciarelli, Sandra Miceli, Cristina |
author_facet |
Yang, Guang Yao, Hua Mozzicafreddo, Matteo Ballarini, Patrizia Pucciarelli, Sandra Miceli, Cristina |
author_sort |
Yang, Guang |
title |
Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
title_short |
Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
title_full |
Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
title_fullStr |
Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
title_full_unstemmed |
Rational Engineering of a Cold-Adapted α-Amylase from the Antarctic Ciliate Euplotes focardii for Simultaneous Improvement of Thermostability and Catalytic Activity |
title_sort |
rational engineering of a cold-adapted α-amylase from the antarctic ciliate euplotes focardii for simultaneous improvement of thermostability and catalytic activity |
publisher |
American Society for Microbiology |
publishDate |
2017 |
url |
http://dx.doi.org/10.1128/aem.00449-17 https://journals.asm.org/doi/pdf/10.1128/AEM.00449-17 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Applied and Environmental Microbiology volume 83, issue 13 ISSN 0099-2240 1098-5336 |
op_rights |
http://creativecommons.org/licenses/by/4.0/ https://journals.asm.org/non-commercial-tdm-license |
op_doi |
https://doi.org/10.1128/aem.00449-17 |
container_title |
Applied and Environmental Microbiology |
container_volume |
83 |
container_issue |
13 |
_version_ |
1798836574650105856 |