A new chitosanase gene from a Nocardioides sp. is a third member of glycosyl hydrolase family 46.
Strain N106, a newly isolated soil actinomycete classified in the genus Nocardioides on the basis of its chemotaxonomy, produced an extracellular chitosanase and was highly active in chitosan degradation. A gene library of Nocardioides sp. N106 was constructed in the shuttle vector pFD666 and recombinant plasmids carrying the chitosanase gene (csnN106) were identified using the 5'-terminal portion of the chitosanase gene from Streptomyces sp. N174 as a hybridization probe. One plasmid, pCSN106-2, was used to transform Streptomyces lividans TK24. The chitosanase produced by S. lividans (pCSN106-2) is a protein of 29.5 kDa, with a pI 8.1, and hydrolyses chitosan by an endo-mechanism giving a mixture of dimers and trimers as end-products. N-terminal sequencing revealed that the mature chitosanase is a mixture of two enzyme forms differing by one N-terminal amino acid. The csnN106 gene is 79.5% homologous to the csn gene from Streptomyces sp. N174. At the amino acid level, both chitosanases are homologous at 74.4% and hydrophobic cluster analysis revealed a strict conservation of structural features. This chitosanase is the third known member of family 46 of glycosyl hydrolases.
Masson
J Y
JY
Département de Biologie, Faculté des Sciences, Université de Sherbrooke, QC, Canada.
Boucher
I
I
Neugebauer
W A
WA
Ramotar
D
D
Brzezinski
R
R
D000192:Actinomycetales / Q000201:enzymology / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006026:Glycoside Hydrolases / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000235:genetics
D011994:Recombinant Proteins; D006026:Glycoside Hydrolases; C019868:chitosanase