Structural insights of the enzymes from the chitin utilization locus of Flavobacterium johnsoniae
Journal article, 2020

Chitin is one of the most abundant renewable organic materials found on earth. The chitin utilization locus in Flavobacterium johnsoniae, which encodes necessary proteins for complete enzymatic depolymerization of crystalline chitin, has recently been characterized but no detailed structural information on the enzymes was provided. Here we present protein structures of the F. johnsoniae chitobiase (FjGH20) and chitinase B (FjChiB). FjGH20 is a multi-domain enzyme with a helical domain not before observed in other chitobiases and a domain organization reminiscent of GH84 (beta -N-acetylglucosaminidase) family members. The structure of FjChiB reveals that the protein lacks loops and regions associated with exo-acting activity in other chitinases and instead has a more solvent accessible substrate binding cleft, which is consistent with its endo-chitinase activity. Additionally, small angle X-ray scattering data were collected for the internal 70 kDa region that connects the N- and C-terminal chitinase domains of the unique 158 kDa multi-domain chitinase A (FjChiA). The resulting model of the molecular envelope supports bioinformatic predictions of the region comprising six domains, each with similarities to either Fn3-like or Ig-like domains. Taken together, the results provide insights into chitin utilization by F. johnsoniae and reveal structural diversity in bacterial chitin metabolism.


Scott Mazurkewich

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Ronny Helland

University of Tromsø – The Arctic University of Norway

Alasdair Mackenzie

Norwegian University of Life Sciences

Vincent G. H. Eijsink

Norwegian University of Life Sciences

Phillip B. Pope

Norwegian University of Life Sciences

Gisela Branden

University of Gothenburg

Johan Larsbrink

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Scientific Reports

2045-2322 (ISSN)

Vol. 10 1 13775

Subject Categories

Biochemistry and Molecular Biology

Structural Biology

Biocatalysis and Enzyme Technology





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