Τίτλος:
The crystal structure of a streptomyces thermoviolaceus thermophilic chitinase known for its refolding efficiency
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
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. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Συγγραφείς:
Malecki, P.H.
Bejger, M.
Rypniewski, W.
Vorgias, C.E.
Περιοδικό:
International Journal of Molecular Sciences
Λέξεις-κλειδιά:
amino acid; chitinase; disulfide; chitinase, amino acid substitution; Article; Aspergillus niger; Bacillus thuringiensis; binding site; column chromatography; conformational transition; cross linking; crystal structure; crystallization; enzyme active site; enzyme activity; enzyme substrate complex; enzymology; hydrophobic interaction chromatography; hydrophobicity; mass spectrometry; nonhuman; plasmid; protein degradation; protein interaction; protein purification; protein secondary structure; Streptomyces; Streptomyces thermoviolaceus; thermophilic bacterium; thermostability; X ray crystallography; catalysis; chemistry; enzymology; genetics; molecular model; protein conformation; protein folding; protein refolding; Streptomyces; structure activity relation, Amino Acid Substitution; Binding Sites; Catalysis; Catalytic Domain; Chitinases; Crystallography, X-Ray; Disulfides; Models, Molecular; Protein Conformation; Protein Folding; Protein Refolding; Streptomyces; Structure-Activity Relationship
DOI:
10.3390/ijms21082892
