New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM

Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, an N-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation...

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Detalles Bibliográficos
Autores principales: Fadel, Firas, Zhao, Yuguang, Cachau, Raul, Cousido Siah, Alexandra, Ruiz, Francesc X., Harlos, Karl, Howard, Eduardo Ignacio, Mitschler, Andre, Podjarny, Alberto Daniel
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2015
Materias:
Biología
Crystal structure
Chitotriosidase
Catalytic mechanism
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/99593
https://ri.conicet.gov.ar/11336/47887
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-99593
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Biología
Crystal structure
Chitotriosidase
Catalytic mechanism
spellingShingle Biología
Crystal structure
Chitotriosidase
Catalytic mechanism
Fadel, Firas
Zhao, Yuguang
Cachau, Raul
Cousido Siah, Alexandra
Ruiz, Francesc X.
Harlos, Karl
Howard, Eduardo Ignacio
Mitschler, Andre
Podjarny, Alberto Daniel
New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
topic_facet Biología
Crystal structure
Chitotriosidase
Catalytic mechanism
description Chitotriosidase (CHIT1) is a human chitinase belonging to the highly conserved glycosyl hydrolase family 18 (GH18). GH18 enzymes hydrolyze chitin, an N-acetylglucosamine polymer synthesized by lower organisms for structural purposes. Recently, CHIT1 has attracted attention owing to its upregulation in immune-system disorders and as a marker of Gaucher disease. The 39 kDa catalytic domain shows a conserved cluster of three acidic residues, Glu140, Asp138 and Asp136, involved in the hydrolysis reaction. Under an excess concentration of substrate, CHIT1 and other homologues perform an additional activity, transglycosylation. To understand the catalytic mechanism of GH18 chitinases and the dual enzymatic activity, the structure and mechanism of CHIT1 were analyzed in detail. The resolution of the crystals of the catalytic domain was improved from 1.65 Å (PDB entry 1waw ) to 0.95-1.10 Å for the apo and pseudo-apo forms and the complex with chitobiose, allowing the determination of the protonation states within the active site. This information was extended by hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. The results suggest a new mechanism involving changes in the conformation and protonation state of the catalytic triad, as well as a new role for Tyr27, providing new insights into the hydrolysis and transglycosylation activities.
format Articulo
Preprint
author Fadel, Firas
Zhao, Yuguang
Cachau, Raul
Cousido Siah, Alexandra
Ruiz, Francesc X.
Harlos, Karl
Howard, Eduardo Ignacio
Mitschler, Andre
Podjarny, Alberto Daniel
author_facet Fadel, Firas
Zhao, Yuguang
Cachau, Raul
Cousido Siah, Alexandra
Ruiz, Francesc X.
Harlos, Karl
Howard, Eduardo Ignacio
Mitschler, Andre
Podjarny, Alberto Daniel
author_sort Fadel, Firas
title New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
title_short New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
title_full New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
title_fullStr New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
title_full_unstemmed New insights into the enzymatic mechanism of human chitotriosidase (CHIT1) catalytic domain by atomic resolution X-ray diffraction and hybrid QM/MM
title_sort new insights into the enzymatic mechanism of human chitotriosidase (chit1) catalytic domain by atomic resolution x-ray diffraction and hybrid qm/mm
publishDate 2015
url http://sedici.unlp.edu.ar/handle/10915/99593
https://ri.conicet.gov.ar/11336/47887
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