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Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase

[Image: see text] l-Asparaginases of bacterial origin are a mainstay of acute lymphoblastic leukemia treatment. The mechanism of action of these enzyme drugs is associated with their capacity to deplete the amino acid l-asparagine from the blood. However, clinical use of bacterial l-asparaginases is...

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Autores principales: Nguyen, Hien Anh, Su, Ying, Lavie, Arnon
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2016
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776285/
https://www.ncbi.nlm.nih.gov/pubmed/26855287
http://dx.doi.org/10.1021/acs.biochem.5b01351
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author Nguyen, Hien Anh
Su, Ying
Lavie, Arnon
author_facet Nguyen, Hien Anh
Su, Ying
Lavie, Arnon
author_sort Nguyen, Hien Anh
collection PubMed
description [Image: see text] l-Asparaginases of bacterial origin are a mainstay of acute lymphoblastic leukemia treatment. The mechanism of action of these enzyme drugs is associated with their capacity to deplete the amino acid l-asparagine from the blood. However, clinical use of bacterial l-asparaginases is complicated by their dual l-asparaginase and l-glutaminase activities. The latter, even though representing only ∼10% of the overall activity, is partially responsible for the observed toxic side effects. Hence, l-asparaginases devoid of l-glutaminase activity hold potential as safer drugs. Understanding the key determinants of l-asparaginase substrate specificity is a prerequisite step toward the development of enzyme variants with reduced toxicity. Here we present crystal structures of the Erwinia chrysanthemil-asparaginase in complex with l-aspartic acid and with l-glutamic acid. These structures reveal two enzyme conformations—open and closed—corresponding to the inactive and active states, respectively. The binding of ligands induces the positioning of the catalytic Thr15 into its active conformation, which in turn allows for the ordering and closure of the flexible N-terminal loop. Notably, l-aspartic acid is more efficient than l-glutamic acid in inducing the active positioning of Thr15. Structural elements explaining the preference of the enzyme for l-asparagine over l-glutamine are discussed with guidance to the future development of more specific l-asparaginases.
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spelling pubmed-47762852016-03-07 Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase Nguyen, Hien Anh Su, Ying Lavie, Arnon Biochemistry [Image: see text] l-Asparaginases of bacterial origin are a mainstay of acute lymphoblastic leukemia treatment. The mechanism of action of these enzyme drugs is associated with their capacity to deplete the amino acid l-asparagine from the blood. However, clinical use of bacterial l-asparaginases is complicated by their dual l-asparaginase and l-glutaminase activities. The latter, even though representing only ∼10% of the overall activity, is partially responsible for the observed toxic side effects. Hence, l-asparaginases devoid of l-glutaminase activity hold potential as safer drugs. Understanding the key determinants of l-asparaginase substrate specificity is a prerequisite step toward the development of enzyme variants with reduced toxicity. Here we present crystal structures of the Erwinia chrysanthemil-asparaginase in complex with l-aspartic acid and with l-glutamic acid. These structures reveal two enzyme conformations—open and closed—corresponding to the inactive and active states, respectively. The binding of ligands induces the positioning of the catalytic Thr15 into its active conformation, which in turn allows for the ordering and closure of the flexible N-terminal loop. Notably, l-aspartic acid is more efficient than l-glutamic acid in inducing the active positioning of Thr15. Structural elements explaining the preference of the enzyme for l-asparagine over l-glutamine are discussed with guidance to the future development of more specific l-asparaginases. American Chemical Society 2016-02-08 2016-03-01 /pmc/articles/PMC4776285/ /pubmed/26855287 http://dx.doi.org/10.1021/acs.biochem.5b01351 Text en Copyright © 2016 American Chemical Society This is an open access article published under an ACS AuthorChoice License (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html) , which permits copying and redistribution of the article or any adaptations for non-commercial purposes.
spellingShingle Nguyen, Hien Anh
Su, Ying
Lavie, Arnon
Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title_full Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title_fullStr Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title_full_unstemmed Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title_short Structural Insight into Substrate Selectivity of Erwinia chrysanthemil-Asparaginase
title_sort structural insight into substrate selectivity of erwinia chrysanthemil-asparaginase
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4776285/
https://www.ncbi.nlm.nih.gov/pubmed/26855287
http://dx.doi.org/10.1021/acs.biochem.5b01351
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