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Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase

Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for it...

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Autores principales: Díaz, Roberto Efraín, Ecker, Andrew K., Correy, Galen J., Asthana, Pooja, Young, Iris D., Faust, Bryan, Thompson, Michael C., Seiple, Ian B., Van Dyken, Steven J., Locksley, Richard M., Fraser, James S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10312649/
https://www.ncbi.nlm.nih.gov/pubmed/37398339
http://dx.doi.org/10.1101/2023.06.03.542675
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author Díaz, Roberto Efraín
Ecker, Andrew K.
Correy, Galen J.
Asthana, Pooja
Young, Iris D.
Faust, Bryan
Thompson, Michael C.
Seiple, Ian B.
Van Dyken, Steven J.
Locksley, Richard M.
Fraser, James S.
author_facet Díaz, Roberto Efraín
Ecker, Andrew K.
Correy, Galen J.
Asthana, Pooja
Young, Iris D.
Faust, Bryan
Thompson, Michael C.
Seiple, Ian B.
Van Dyken, Steven J.
Locksley, Richard M.
Fraser, James S.
author_sort Díaz, Roberto Efraín
collection PubMed
description Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high resolution crystal structures of mAMCase in complex with chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation.
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spelling pubmed-103126492023-07-01 Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase Díaz, Roberto Efraín Ecker, Andrew K. Correy, Galen J. Asthana, Pooja Young, Iris D. Faust, Bryan Thompson, Michael C. Seiple, Ian B. Van Dyken, Steven J. Locksley, Richard M. Fraser, James S. bioRxiv Article Chitin is an abundant biopolymer and pathogen-associated molecular pattern that stimulates a host innate immune response. Mammals express chitin-binding and chitin-degrading proteins to remove chitin from the body. One of these proteins, Acidic Mammalian Chitinase (AMCase), is an enzyme known for its ability to function under acidic conditions in the stomach but is also active in tissues with more neutral pHs, such as the lung. Here, we used a combination of biochemical, structural, and computational modeling approaches to examine how the mouse homolog (mAMCase) can act in both acidic and neutral environments. We measured kinetic properties of mAMCase activity across a broad pH range, quantifying its unusual dual activity optima at pH 2 and 7. We also solved high resolution crystal structures of mAMCase in complex with chitin, where we identified extensive conformational ligand heterogeneity. Leveraging these data, we conducted molecular dynamics simulations that suggest how a key catalytic residue could be protonated via distinct mechanisms in each of the two environmental pH ranges. These results integrate structural, biochemical, and computational approaches to deliver a more complete understanding of the catalytic mechanism governing mAMCase activity at different pH. Engineering proteins with tunable pH optima may provide new opportunities to develop improved enzyme variants, including AMCase, for therapeutic purposes in chitin degradation. Cold Spring Harbor Laboratory 2023-06-28 /pmc/articles/PMC10312649/ /pubmed/37398339 http://dx.doi.org/10.1101/2023.06.03.542675 Text en https://creativecommons.org/licenses/by/4.0/This work is licensed under a Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/) , which allows reusers to distribute, remix, adapt, and build upon the material in any medium or format, so long as attribution is given to the creator. The license allows for commercial use.
spellingShingle Article
Díaz, Roberto Efraín
Ecker, Andrew K.
Correy, Galen J.
Asthana, Pooja
Young, Iris D.
Faust, Bryan
Thompson, Michael C.
Seiple, Ian B.
Van Dyken, Steven J.
Locksley, Richard M.
Fraser, James S.
Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title_full Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title_fullStr Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title_full_unstemmed Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title_short Structural characterization of ligand binding and pH-specific enzymatic activity of mouse Acidic Mammalian Chitinase
title_sort structural characterization of ligand binding and ph-specific enzymatic activity of mouse acidic mammalian chitinase
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10312649/
https://www.ncbi.nlm.nih.gov/pubmed/37398339
http://dx.doi.org/10.1101/2023.06.03.542675
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