2cjl
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CRYSTAL STRUCTURE AND ENZYMATIC PROPERTIES OF A BACTERIAL FAMILY 19 CHITINASE REVEAL DIFFERENCES WITH PLANT ENZYMES
OverviewOverview
We describe the cloning, overexpression, purification, characterization, and crystal structure of chitinase G, a single-domain family 19 chitinase, from the Gram-positive bacterium Streptomyces coelicolor A3(2). Although, chitinase G was not capable of releasing 4-methylumbelliferyl from, artificial chitooligosaccharide substrates, it was capable of degrading, longer chitooligosaccharides at rates similar to those observed for other, chitinases. The enzyme was also capable of degrading a colored colloidal, chitin substrate (carboxymethyl-chitin-remazol-brilliant violet) and a, small, presumably amorphous, subfraction of alpha-chitin and beta-chitin, but was not capable of degrading crystalline chitin completely. The, crystal structures of chitinase G and a related Streptomyces chitinase, chitinase C [Kezuka Y, Ohishi M, Itoh Y, Watanabe J, Mitsutomi M, Watanabe, T & Nonaka T (2006) J Mol Biol358, 472-484], showed that these bacterial, family 19 chitinases lack several loops that extend the substrate-binding, grooves in family 19 chitinases from plants. In accordance with these, structural features, detailed analysis of the degradation of, chitooligosaccharides by chitinase G showed that the enzyme has only four, subsites (- 2 to + 2), as opposed to six (- 3 to + 3) for plant enzymes., The most prominent structural difference leading to reduced size of the, substrate-binding groove is the deletion of a 13-residue loop between the, two putatively catalytic glutamates. The importance of these two residues, for catalysis was confirmed by a site-directed mutagenesis study.
About this StructureAbout this Structure
2CJL is a Single protein structure of sequence from Streptomyces coelicolor with ZN as ligand. Active as Chitinase, with EC number 3.2.1.14 Structure known Active Site: AC1. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure and enzymatic properties of a bacterial family 19 chitinase reveal differences from plant enzymes., Hoell IA, Dalhus B, Heggset EB, Aspmo SI, Eijsink VG, FEBS J. 2006 Nov;273(21):4889-900. Epub 2006 Sep 28. PMID:17010167
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