Stability and Structural Analysis of Alpha-Amylase from the Antarctic Psychrophile Alteromonas Haloplanctis A23
peer reviewed 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...
Published in: | European Journal of Biochemistry |
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Blackwell
1994
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Online Access: | https://orbi.uliege.be/handle/2268/16330 https://orbi.uliege.be/bitstream/2268/16330/1/EJB_94_AHA.pdf https://doi.org/10.1111/j.1432-1033.1994.tb18883.x |
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ftorbi:oai:orbi.ulg.ac.be:2268/16330 2024-04-21T07:48:25+00:00 Stability and Structural Analysis of Alpha-Amylase from the Antarctic Psychrophile Alteromonas Haloplanctis A23 Feller, Georges Payan, F. Theys, F. Qian, M. Haser, R. Gerday, Charles 1994-06-01 https://orbi.uliege.be/handle/2268/16330 https://orbi.uliege.be/bitstream/2268/16330/1/EJB_94_AHA.pdf https://doi.org/10.1111/j.1432-1033.1994.tb18883.x en eng Blackwell urn:issn:0014-2956 urn:issn:1432-1033 https://orbi.uliege.be/handle/2268/16330 info:hdl:2268/16330 https://orbi.uliege.be/bitstream/2268/16330/1/EJB_94_AHA.pdf doi:10.1111/j.1432-1033.1994.tb18883.x scopus-id:2-s2.0-0028289989 info:pmid:8020481 open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess European Journal of Biochemistry, 222 (2), 441-7 (1994-06-01) Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire journal article http://purl.org/coar/resource_type/c_6501 info:eu-repo/semantics/article peer reviewed 1994 ftorbi https://doi.org/10.1111/j.1432-1033.1994.tb18883.x 2024-03-27T14:52:24Z peer reviewed 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. Article in Journal/Newspaper Antarc* Antarctic University of Liège: ORBi (Open Repository and Bibliography) European Journal of Biochemistry 222 2 441 447 |
institution |
Open Polar |
collection |
University of Liège: ORBi (Open Repository and Bibliography) |
op_collection_id |
ftorbi |
language |
English |
topic |
Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire |
spellingShingle |
Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire Feller, Georges Payan, F. Theys, F. Qian, M. Haser, R. Gerday, Charles Stability and Structural Analysis of Alpha-Amylase from the Antarctic Psychrophile Alteromonas Haloplanctis A23 |
topic_facet |
Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire |
description |
peer reviewed 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. |
format |
Article in Journal/Newspaper |
author |
Feller, Georges Payan, F. Theys, F. Qian, M. Haser, R. Gerday, Charles |
author_facet |
Feller, Georges Payan, F. Theys, F. Qian, M. Haser, R. Gerday, Charles |
author_sort |
Feller, Georges |
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 |
Blackwell |
publishDate |
1994 |
url |
https://orbi.uliege.be/handle/2268/16330 https://orbi.uliege.be/bitstream/2268/16330/1/EJB_94_AHA.pdf https://doi.org/10.1111/j.1432-1033.1994.tb18883.x |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
European Journal of Biochemistry, 222 (2), 441-7 (1994-06-01) |
op_relation |
urn:issn:0014-2956 urn:issn:1432-1033 https://orbi.uliege.be/handle/2268/16330 info:hdl:2268/16330 https://orbi.uliege.be/bitstream/2268/16330/1/EJB_94_AHA.pdf doi:10.1111/j.1432-1033.1994.tb18883.x scopus-id:2-s2.0-0028289989 info:pmid:8020481 |
op_rights |
open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess |
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_ |
1796949462810099712 |