Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis
peer reviewed The cold-adapted cellulase CelG has been purified from the culture supernatant of the Antarctic bacterium Pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in Escherichia coli. This cellulase is composed of three structurally an...
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Portland Press
2004
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ftorbi:oai:orbi.ulg.ac.be:2268/15606 2024-04-21T07:52:05+00:00 Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis Garsoux, Geneviève Lamotte, Josette Gerday, Charles Feller, Georges 2004-12-01 https://orbi.uliege.be/handle/2268/15606 https://orbi.uliege.be/bitstream/2268/15606/1/BiochemJ_2004_cellulase.pdf https://doi.org/10.1042/BJ20040325 en eng Portland Press urn:issn:0264-6021 urn:issn:1470-8728 https://orbi.uliege.be/handle/2268/15606 info:hdl:2268/15606 https://orbi.uliege.be/bitstream/2268/15606/1/BiochemJ_2004_cellulase.pdf doi:10.1042/BJ20040325 scopus-id:2-s2.0-10644264362 info:pmid:15287848 open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess Biochemical Journal, 384 (Pt 2), 247-253 (2004-12-01) carbohydrate-binding module cellulase extremophile glycoside hydrolase Pseudoalteromonas haloplanktis psychrophile 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 2004 ftorbi https://doi.org/10.1042/BJ20040325 2024-03-27T14:55:11Z peer reviewed The cold-adapted cellulase CelG has been purified from the culture supernatant of the Antarctic bacterium Pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in Escherichia coli. This cellulase is composed of three structurally and functionally distinct regions: an N-terminal catalytic domain belonging to glycosidase family 5 and a C-terminal cellulose-binding domain belonging to carbohydrate-binding module family 5. The linker of 107 residues connecting both domains is one of the longest found in cellulases, and optimizes substrate accessibility to the catalytic domain by drastically increasing the Surface of cellulose available to a bound enzyme molecule. The psychrophilic enzyme is closely related to the cellulase Cel5 from Erwinia chrysanthemi. Both k(cat) and k(cat)/K-m values at 4 degreesC for the psychrophilic cellulase are similar to the values for Cel5 at 30-35 degreesC, suggesting temperature adaptation of the kinetic parameters. The thermodynamic parameters of activation of CelG suggest a heat-labile, relatively disordered active site with low substrate affinity, in agreement with the experimental data. The structure of CelG has been constructed by homology modelling with a molecule of cellotetraose docked into the active site. No structural alteration related to cold-activity can be found in the catalytic cleft, whereas several structural factors in the overall structure can explain the weak thermal stability, suggesting that the loss of stability provides the required active-site mobility at low temperatures. Article in Journal/Newspaper Antarc* Antarctic University of Liège: ORBi (Open Repository and Bibliography) Biochemical Journal 384 2 247 253 |
institution |
Open Polar |
collection |
University of Liège: ORBi (Open Repository and Bibliography) |
op_collection_id |
ftorbi |
language |
English |
topic |
carbohydrate-binding module cellulase extremophile glycoside hydrolase Pseudoalteromonas haloplanktis psychrophile Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire |
spellingShingle |
carbohydrate-binding module cellulase extremophile glycoside hydrolase Pseudoalteromonas haloplanktis psychrophile Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire Garsoux, Geneviève Lamotte, Josette Gerday, Charles Feller, Georges Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
topic_facet |
carbohydrate-binding module cellulase extremophile glycoside hydrolase Pseudoalteromonas haloplanktis psychrophile Life sciences Biochemistry biophysics & molecular biology Sciences du vivant Biochimie biophysique & biologie moléculaire |
description |
peer reviewed The cold-adapted cellulase CelG has been purified from the culture supernatant of the Antarctic bacterium Pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in Escherichia coli. This cellulase is composed of three structurally and functionally distinct regions: an N-terminal catalytic domain belonging to glycosidase family 5 and a C-terminal cellulose-binding domain belonging to carbohydrate-binding module family 5. The linker of 107 residues connecting both domains is one of the longest found in cellulases, and optimizes substrate accessibility to the catalytic domain by drastically increasing the Surface of cellulose available to a bound enzyme molecule. The psychrophilic enzyme is closely related to the cellulase Cel5 from Erwinia chrysanthemi. Both k(cat) and k(cat)/K-m values at 4 degreesC for the psychrophilic cellulase are similar to the values for Cel5 at 30-35 degreesC, suggesting temperature adaptation of the kinetic parameters. The thermodynamic parameters of activation of CelG suggest a heat-labile, relatively disordered active site with low substrate affinity, in agreement with the experimental data. The structure of CelG has been constructed by homology modelling with a molecule of cellotetraose docked into the active site. No structural alteration related to cold-activity can be found in the catalytic cleft, whereas several structural factors in the overall structure can explain the weak thermal stability, suggesting that the loss of stability provides the required active-site mobility at low temperatures. |
format |
Article in Journal/Newspaper |
author |
Garsoux, Geneviève Lamotte, Josette Gerday, Charles Feller, Georges |
author_facet |
Garsoux, Geneviève Lamotte, Josette Gerday, Charles Feller, Georges |
author_sort |
Garsoux, Geneviève |
title |
Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
title_short |
Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
title_full |
Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
title_fullStr |
Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
title_full_unstemmed |
Kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the Antarctic bacterium Pseudoalteromonas haloplanktis |
title_sort |
kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the antarctic bacterium pseudoalteromonas haloplanktis |
publisher |
Portland Press |
publishDate |
2004 |
url |
https://orbi.uliege.be/handle/2268/15606 https://orbi.uliege.be/bitstream/2268/15606/1/BiochemJ_2004_cellulase.pdf https://doi.org/10.1042/BJ20040325 |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Biochemical Journal, 384 (Pt 2), 247-253 (2004-12-01) |
op_relation |
urn:issn:0264-6021 urn:issn:1470-8728 https://orbi.uliege.be/handle/2268/15606 info:hdl:2268/15606 https://orbi.uliege.be/bitstream/2268/15606/1/BiochemJ_2004_cellulase.pdf doi:10.1042/BJ20040325 scopus-id:2-s2.0-10644264362 info:pmid:15287848 |
op_rights |
open access http://purl.org/coar/access_right/c_abf2 info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1042/BJ20040325 |
container_title |
Biochemical Journal |
container_volume |
384 |
container_issue |
2 |
container_start_page |
247 |
op_container_end_page |
253 |
_version_ |
1796935342546223104 |