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The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency

Analyzing the structure of proteins from extremophiles is a promising way to study the rules governing the protein structure, because such proteins are results of structural and functional optimization under well-defined conditions. Studying the structure of chitinases addresses an interesting aspec...

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Autores principales: Malecki, Piotr H., Bejger, Magdalena, Rypniewski, Wojciech, Vorgias, Constantinos E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215727/
https://www.ncbi.nlm.nih.gov/pubmed/32326166
http://dx.doi.org/10.3390/ijms21082892
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author Malecki, Piotr H.
Bejger, Magdalena
Rypniewski, Wojciech
Vorgias, Constantinos E.
author_facet Malecki, Piotr H.
Bejger, Magdalena
Rypniewski, Wojciech
Vorgias, Constantinos E.
author_sort Malecki, Piotr H.
collection PubMed
description Analyzing the structure of proteins from extremophiles is a promising way to study the rules governing the protein structure, because such proteins are results of structural and functional optimization under well-defined conditions. Studying the structure of chitinases addresses an interesting aspect of enzymology, because chitin, while being the world’s second most abundant biopolymer, is also a recalcitrant substrate. The crystal structure of a thermostable chitinase from Streptomyces thermoviolaceus (StChi40) has been solved revealing a β/α-barrel (TIM-barrel) fold with an α+β insertion domain. This is the first chitinase structure of the multi-chitinase system of S. thermoviolaceus. The protein is also known to refold efficiently after thermal or chemical denaturation. StChi40 is structurally close to the catalytic domain of psychrophilic chitinase B from Arthrobacter TAD20. Differences are noted in comparison to the previously examined chitinases, particularly in the substrate-binding cleft. A comparison of the thermophilic enzyme with its psychrophilic homologue revealed structural features that could be attributed to StChi40’s thermal stability: compactness of the structure with trimmed surface loops and unique disulfide bridges, one of which is additionally stabilized by S–π interactions with aromatic rings. Uncharacteristically for thermophilic proteins, StChi40 has fewer salt bridges than its mesophilic and psychrophilic homologues.
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spelling pubmed-72157272020-05-22 The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency Malecki, Piotr H. Bejger, Magdalena Rypniewski, Wojciech Vorgias, Constantinos E. Int J Mol Sci Article Analyzing the structure of proteins from extremophiles is a promising way to study the rules governing the protein structure, because such proteins are results of structural and functional optimization under well-defined conditions. Studying the structure of chitinases addresses an interesting aspect of enzymology, because chitin, while being the world’s second most abundant biopolymer, is also a recalcitrant substrate. The crystal structure of a thermostable chitinase from Streptomyces thermoviolaceus (StChi40) has been solved revealing a β/α-barrel (TIM-barrel) fold with an α+β insertion domain. This is the first chitinase structure of the multi-chitinase system of S. thermoviolaceus. The protein is also known to refold efficiently after thermal or chemical denaturation. StChi40 is structurally close to the catalytic domain of psychrophilic chitinase B from Arthrobacter TAD20. Differences are noted in comparison to the previously examined chitinases, particularly in the substrate-binding cleft. A comparison of the thermophilic enzyme with its psychrophilic homologue revealed structural features that could be attributed to StChi40’s thermal stability: compactness of the structure with trimmed surface loops and unique disulfide bridges, one of which is additionally stabilized by S–π interactions with aromatic rings. Uncharacteristically for thermophilic proteins, StChi40 has fewer salt bridges than its mesophilic and psychrophilic homologues. MDPI 2020-04-21 /pmc/articles/PMC7215727/ /pubmed/32326166 http://dx.doi.org/10.3390/ijms21082892 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Malecki, Piotr H.
Bejger, Magdalena
Rypniewski, Wojciech
Vorgias, Constantinos E.
The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title_full The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title_fullStr The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title_full_unstemmed The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title_short The Crystal Structure of a Streptomyces thermoviolaceus Thermophilic Chitinase Known for Its Refolding Efficiency
title_sort crystal structure of a streptomyces thermoviolaceus thermophilic chitinase known for its refolding efficiency
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7215727/
https://www.ncbi.nlm.nih.gov/pubmed/32326166
http://dx.doi.org/10.3390/ijms21082892
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