Efficient chito-oligosaccharide utilization requires two TonB-dependent transporters and one hexosaminidase in Cellvibrio japonicus
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Type of Work56 pages
Citation of Original PublicationMonge, EC, Gardner, JG. Efficient chito-oligosaccharide utilization requires two TonB-dependent transporters and one hexosaminidase in Cellvibrio japonicus. Mol Microbiol. 2021; 116: 366– 380. https://doi.org/10.1111/mmi.14717
RightsThis is the peer reviewed version of the following article: Monge, EC, Gardner, JG. Efficient chito-oligosaccharide utilization requires two TonB-dependent transporters and one hexosaminidase in Cellvibrio japonicus. Mol Microbiol. 2021; 116: 366– 380. https://doi.org/10.1111/mmi.14717, which has been published in final form at https://doi.org/10.1111/mmi.14717. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
Chitin utilization by microbes plays a significant role in biosphere carbon and nitrogen cycling, and studying the microbial approaches used to degrade chitin will facilitate our understanding of bacterial strategies to degrade a broad range of recalcitrant polysaccharides. The early stages of chitin depolymerization by the bacterium Cellvibrio japonicus have been characterized and are dependent on one chitin-specific lytic polysaccharide monooxygenase and nonredundant glycoside hydrolases from the family GH18 to generate chito-oligosaccharides for entry into metabolism. Here, we describe the mechanisms for the latter stages of chitin utilization by C. japonicus with an emphasis on the fate of chito-oligosaccharides. Our systems biology approach combined transcriptomics and bacterial genetics using ecologically relevant substrates to determine the essential mechanisms for chito-oligosaccharide transport and catabolism in C. japonicus. Using RNAseq analysis we found a coordinated expression of genes that encode polysaccharide-degrading enzymes. Mutational analysis determined that the hex20B gene product, predicted to encode a hexosaminidase, was required for efficient utilization of chito-oligosaccharides. Furthermore, two gene loci (CJA_0353 and CJA_1157), which encode putative TonB-dependent transporters, were also essential for chito-oligosaccharides utilization. This study further develops our model of C. japonicus chitin metabolism and may be predictive for other environmentally or industrially important bacteria.