Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23.
International audience The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees...
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ftunivlyon1:oai:HAL:hal-00313574v1 2023-05-15T13:44:38+02:00 Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. Feller, G. Payan, F. Theys, F. Qian, M. Haser, R. Gerday, C. Institut de biologie et chimie des protéines Lyon (IBCP) Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS) 1994 https://hal.science/hal-00313574 en eng HAL CCSD Wiley hal-00313574 https://hal.science/hal-00313574 ISSN: 0014-2956 EISSN: 1432-1327 European Journal of Biochemistry https://hal.science/hal-00313574 European Journal of Biochemistry, 1994, 222, pp.441-447 [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology info:eu-repo/semantics/article Journal articles 1994 ftunivlyon1 2023-04-07T11:52:47Z International audience The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees 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 alpha-amylase, homology modelling of the psychrophilic alpha-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 (beta/alpha)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 Ca2+ (Kd = 44 nM) and for Cl- (Kd = 1.2 mM at 4 degrees C) can result from single amino acid substitutions in the Ca(2+)-binding and Cl(-)-binding sites and can also affect the compactness of alpha-amylase.The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees C and a lower conformational stability estimated as 10 kJ.mol-1 with respect to the porcine enzyme. It is proposed that both ... Article in Journal/Newspaper Antarc* Antarctic HAL Lyon 1 (University Claude Bernard Lyon 1) Antarctic The Antarctic |
institution |
Open Polar |
collection |
HAL Lyon 1 (University Claude Bernard Lyon 1) |
op_collection_id |
ftunivlyon1 |
language |
English |
topic |
[SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology |
spellingShingle |
[SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology Feller, G. Payan, F. Theys, F. Qian, M. Haser, R. Gerday, C. Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
topic_facet |
[SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology |
description |
International audience The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees 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 alpha-amylase, homology modelling of the psychrophilic alpha-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 (beta/alpha)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 Ca2+ (Kd = 44 nM) and for Cl- (Kd = 1.2 mM at 4 degrees C) can result from single amino acid substitutions in the Ca(2+)-binding and Cl(-)-binding sites and can also affect the compactness of alpha-amylase.The alpha-amylase secreted by the antarctic bacterium Alteromonas haloplanctis displays 66% amino acid sequence similarity with porcine pancreatic alpha-amylase. The psychrophilic alpha-amylase is however characterized by a sevenfold higher kcat and kcat/Km values at 4 degrees C and a lower conformational stability estimated as 10 kJ.mol-1 with respect to the porcine enzyme. It is proposed that both ... |
author2 |
Institut de biologie et chimie des protéines Lyon (IBCP) Université Claude Bernard Lyon 1 (UCBL) Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Feller, G. Payan, F. Theys, F. Qian, M. Haser, R. Gerday, C. |
author_facet |
Feller, G. Payan, F. Theys, F. Qian, M. Haser, R. Gerday, C. |
author_sort |
Feller, G. |
title |
Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
title_short |
Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
title_full |
Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
title_fullStr |
Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
title_full_unstemmed |
Stability and structural analysis of alpha-amylase from the antarctic psychrophile Alteromonas haloplanctis A23. |
title_sort |
stability and structural analysis of alpha-amylase from the antarctic psychrophile alteromonas haloplanctis a23. |
publisher |
HAL CCSD |
publishDate |
1994 |
url |
https://hal.science/hal-00313574 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
ISSN: 0014-2956 EISSN: 1432-1327 European Journal of Biochemistry https://hal.science/hal-00313574 European Journal of Biochemistry, 1994, 222, pp.441-447 |
op_relation |
hal-00313574 https://hal.science/hal-00313574 |
_version_ |
1766204259929423872 |