title: Purification, cloning, and sequence analysis of beta-N-acetylglucosaminidase from the chitinolytic bacterium Aeromonas hydrophila strain SUWA-9.
abstract: A chitinolytic bacterium was isolated from Lake Suwa and identified as Aeromonas hydrophila strain SUWA-9. The strain grew well on a synthetic medium containing colloidal chitin as sole carbon source. Chitin-degrading activity was induced by colloidal chitin or N-acetylglucosamine (GlcNAc). Most of the activity, however, was not detected in culture fluid but was associated with cells. A beta-N-acetylglucosaminidase was purified after it was solubilized from cells by sonication. The purified enzyme hydrolyzed N-acetylchitooligomers from dimer to pentamer and produced GlcNAc as a final product. The enzyme also hydrolyzed synthetic substrates such as p-nitrophenyl (pNP)-N-acetyl-beta-D-glucosaminide and pNP-N-acetyl-beta-D-galactosaminide. A gene coding for the purified beta-N-acetylglucosaminidase was isolated. The ORF identified is 2661 nucleotides long and encodes a precursor protein of 887 amino acids including a signal peptide of 22 amino acid residues. The amino acid sequence deduced showed a high similarity to those of bacterial beta-N-acetylhexosaminidases classified in family 20 of glycosyl hydrolases.
authors.affiliation: Department of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Nagano, Japan.
authors.forename: Xiqian
authors.initials: X
authors.lastname: Lan
authors.forename: Naomi
authors.initials: N
authors.lastname: Ozawa
authors.forename: Naohide
authors.initials: N
authors.lastname: Nishiwaki
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Kodaira
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Okazaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Shimosaka
mesh_terms: D000118:Acetylglucosaminidase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D016980:Aeromonas hydrophila / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D000595:Amino Acid Sequence; D002686:Chitin / Q000378:metabolism; D002688:Chitinases / Q000378:metabolism; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D002686:Chitin; D002688:Chitinases; D000118:Acetylglucosaminidase