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Characterization of two Listeria innocua chitinases of different sizes that were expressed in Escherichia coli. | LitMetric

Characterization of two Listeria innocua chitinases of different sizes that were expressed in Escherichia coli.

Appl Microbiol Biotechnol

Department of Chemistry and Life Science, Kogakuin University, 2,665-1 Nakano-cho, Hachioji, Tokyo, 192-0015, Japan.

Published: September 2016

AI Article Synopsis

  • Two chitinase genes from the benign bacterium Listeria innocua were expressed in E. coli, leading to the discovery of enzymes important for potential pathogenesis in Listeria monocytogenes.
  • The two recombinant enzymes, LinChi78 and LinChi35, have distinct molecular sizes (82 kDa and 38 kDa) and demonstrate optimal activity in different pH and temperature conditions, with LinChi35 showing superior enzymatic activity on certain substrates.
  • Both enzymes primarily produce dimers from chitin, but exhibit different hydrolyzing behaviors and binding capabilities toward different forms of chitin and cellulose, prompting a comparison of their structural and functional roles.

Article Abstract

Two putative chitinase genes, lin0153 and lin1996, from the nonpathogenic bacterium Listeria innocua were expressed in Escherichia coli, and the gene products were characterized. The genes were close homologs of chitinases from the pathogenic bacterium Listeria monocytogenes, in which chitinases and chitin-binding proteins play important roles in pathogenesis in mice-infection models. The purified recombinant enzymes that are different in size, LinChi78 (lin0153 product) and LinChi35 (lin1996 product)-with molecular masses of 82 and 38 kDa, including vector-derived additional sequences, respectively-exhibited optimum catalytic activity under neutral and acidic conditions at 50 °C, respectively, and were stable over broad pH (4-11) and temperature (4-40 °C) ranges. LinChi35 displayed higher k cat and K M values for 4-nitrophenyl N,N-diacetyl-β-D-chitobioside [4NP-(GlcNAc)2] than LinChi78. Both enzymes produced primarily dimers from colloidal chitin as a substrate. However, LinChi78 and LinChi35 could hydrolyze oligomeric substrates in a processive exo- and nonprocessive endo-manner, respectively, and showed different reactivity toward oligomeric substrates. Both enzymes could bind chitin beads but were different in their binding ability toward crystalline α-chitin and cellulose. The structure-function relationships of these chitinases are discussed in reference to other bacterial chitinases.

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Source
http://dx.doi.org/10.1007/s00253-016-7546-0DOI Listing

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