Systems analysis of the Glycoside Hydrolase family 18 enzymes from Cellvibrio japonicus characterizes essential chitin degradation functions
Loading...
Links to Files
Permanent Link
Author/Creator ORCID
Date
2018
Type of Work
Department
Program
Citation of Original Publication
Estela C. Monge, Tina R. Tuveng, Gustav Vaaje-Kolstad, Vincent G. H. Eijsink, and Jeffrey G. Gardner Systems analysis of the family Glycoside Hydrolase family 18 enzymes from Cellvibrio japonicus characterizes essential chitin degradation functions J. Biol. Chem. jbc.RA117.000849. doi:10.1074/jbc.RA117.000849
Rights
This item may be protected under Title 17 of the U.S. Copyright Law. It is made available by UMBC for non-commercial research and education. For permission to publish or reproduce, please contact the author.
Abstract
Understanding the strategies used by bacteria to degrade polysaccharides constitutes an invaluable tool for biotechnological applications. Bacteria are major mediators of polysaccharide degradation in nature, however the complex mechanisms used to detect, degrade, and consume these substrates are not well understood, especially for recalcitrant polysaccharides such as chitin. It has been previously shown that the model bacterial saprophyte Cellvibrio japonicus is able to catabolize chitin, but little is known about the enzymatic machinery underlying this capability. Previous analyses of the C. japonicus genome and proteome indicated the presence of four family 18 Glycoside Hydrolase (GH18) enzymes, and studies of the proteome indicated that all are involved in chitin utilization. Using a combination of in vitro and in vivo approaches, we have studied the roles of these four chitinases in chitin bioconversion. Genetic analyses showed that only the chi18D gene product is essential for the degradation of chitin substrates. Biochemical characterization of the four enzymes showed functional differences and synergistic effects during chitin degradation, indicating non-redundant roles in the cell. Transcriptomic studies revealed complex regulation of the chitin degradation machinery of C. japonicus and confirmed the importance of CjChi18D and CjLPMO10A, a previously characterized chitin-active enzyme. With this systems biology approach, we deciphered the physiological relevance of the GH18 enzymes for chitin degradation in C. japonicus, and the combination of in vitro and in vivo approaches provided a comprehensive understanding of the initial stages of chitin degradation by this bacterium.