Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23
The α‐amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic α‐amylase. The psychrophilic α‐amylase is however characterized by a sevenfold higher k cat and k cat / K m values at 4°C and a lower conformational stabilit...
Published in: | European Journal of Biochemistry |
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crwiley:10.1111/j.1432-1033.1994.tb18883.x 2024-09-15T17:43:01+00:00 Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 FELLER, Georges PAYAN, Françoise THEYS, Fabienne QIAN, Minxie HASER, Richard GERDAY, Charles 1994 http://dx.doi.org/10.1111/j.1432-1033.1994.tb18883.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1432-1033.1994.tb18883.x https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1994.tb18883.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor European Journal of Biochemistry volume 222, issue 2, page 441-447 ISSN 0014-2956 1432-1033 journal-article 1994 crwiley https://doi.org/10.1111/j.1432-1033.1994.tb18883.x 2024-08-27T04:32:22Z The α‐amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic α‐amylase. The psychrophilic α‐amylase is however characterized by a sevenfold higher k cat and k cat / K m values at 4°C and a lower conformational stability estimated as 10 kJ · mol −1 with respect to the porcine enzyme. It is proposed that both properties arise from an increase in molecular flexibility required to compensate for the reduction of reaction rates at low temperatures. This is supported by the fast denaturation rates induced by temperature, urea or guanidinium chloride and by the shift towards low temperatures of the apparent optimal temperature of activity. When compared with the known three‐dimensional structure of porcine pancreatic α‐amylase, homology modelling of the psychrophilic α‐amylase reveals several features which may be assumed to be responsible for a more flexible, heat‐labile conformation: the lack of several surface salt bridges in the (β/α) 8 domain, the reduction of the number of weakly polar interactions involving an aromatic side chain, a lower hydrophobicity associated with the increased flexibility index of amino acids forming the hydrophobic clusters and by substitutions of proline for alanine residues in loops connecting secondary structures. The weaker affinity of the enzyme for Ca 2+ ( K d = 44 nM) and for Cl − ( K d = 1.2 mM at 4°C) can result from single amino acid substitutions in the Ca 2+ ‐binding and Cl − ‐binding sites and can also affect the compactness of α‐amylase. Article in Journal/Newspaper Antarc* Antarctic Wiley Online Library European Journal of Biochemistry 222 2 441 447 |
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Wiley Online Library |
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crwiley |
language |
English |
description |
The α‐amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic α‐amylase. The psychrophilic α‐amylase is however characterized by a sevenfold higher k cat and k cat / K m values at 4°C and a lower conformational stability estimated as 10 kJ · mol −1 with respect to the porcine enzyme. It is proposed that both properties arise from an increase in molecular flexibility required to compensate for the reduction of reaction rates at low temperatures. This is supported by the fast denaturation rates induced by temperature, urea or guanidinium chloride and by the shift towards low temperatures of the apparent optimal temperature of activity. When compared with the known three‐dimensional structure of porcine pancreatic α‐amylase, homology modelling of the psychrophilic α‐amylase reveals several features which may be assumed to be responsible for a more flexible, heat‐labile conformation: the lack of several surface salt bridges in the (β/α) 8 domain, the reduction of the number of weakly polar interactions involving an aromatic side chain, a lower hydrophobicity associated with the increased flexibility index of amino acids forming the hydrophobic clusters and by substitutions of proline for alanine residues in loops connecting secondary structures. The weaker affinity of the enzyme for Ca 2+ ( K d = 44 nM) and for Cl − ( K d = 1.2 mM at 4°C) can result from single amino acid substitutions in the Ca 2+ ‐binding and Cl − ‐binding sites and can also affect the compactness of α‐amylase. |
format |
Article in Journal/Newspaper |
author |
FELLER, Georges PAYAN, Françoise THEYS, Fabienne QIAN, Minxie HASER, Richard GERDAY, Charles |
spellingShingle |
FELLER, Georges PAYAN, Françoise THEYS, Fabienne QIAN, Minxie HASER, Richard GERDAY, Charles Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
author_facet |
FELLER, Georges PAYAN, Françoise THEYS, Fabienne QIAN, Minxie HASER, Richard GERDAY, Charles |
author_sort |
FELLER, Georges |
title |
Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
title_short |
Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
title_full |
Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
title_fullStr |
Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
title_full_unstemmed |
Stability and structural analysis of α‐amylase from the antarctic psychrophile Alteromonas haloplanctis A23 |
title_sort |
stability and structural analysis of α‐amylase from the antarctic psychrophile alteromonas haloplanctis a23 |
publisher |
Wiley |
publishDate |
1994 |
url |
http://dx.doi.org/10.1111/j.1432-1033.1994.tb18883.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1432-1033.1994.tb18883.x https://febs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1432-1033.1994.tb18883.x |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
European Journal of Biochemistry volume 222, issue 2, page 441-447 ISSN 0014-2956 1432-1033 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1432-1033.1994.tb18883.x |
container_title |
European Journal of Biochemistry |
container_volume |
222 |
container_issue |
2 |
container_start_page |
441 |
op_container_end_page |
447 |
_version_ |
1810489854492934144 |