Characteristics of a Streptomyces coelicolor A3(2) extracellular protein targeting chitin and chitosan.
Upstream of the Streptomyces coelicolor A3(2) chitinase G gene, a small gene (named chb3) is located whose deduced product shares 37% identical amino acids with the previously described CHB1 protein from Streptomyces olivaceoviridis. The chb3 gene and its upstream region were cloned in a multicopy vector and transformed into the plasmid-free Streptomyces lividans TK21 strain. The CHB3 protein (14.9 kDa) was secreted by the S. lividans TK21 transformant during growth in the presence of glucose, N-acetylglucosamine, yeast extract, and chitin. The protein was purified to homogeneity using anionic exchange, hydrophobic interaction chromatographies, and gel filtration. In contrast to CHB1, CHB3 targets alpha-chitin, beta-chitin, and chitosan at pH 6.0 but does so relatively loosely. The ecological implications of the divergence of substrate specificity of various types of chitin-binding proteins are described.
Saito
A
A
FB Biologie/Chemie, Universität Osnabrück, 49069 Osnabrück, Germany.
Miyashita
K
K
Biukovic
G
G
Schrempf
H
H
D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002686:Chitin / Q000031:analogs & derivatives / Q000378:metabolism*; D048271:Chitosan; D004269:DNA, Bacterial / Q000235:genetics; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D014169:Transformation, Bacterial
D001426:Bacterial Proteins; D002352:Carrier Proteins; C433800:Chb3 protein, Streptomyces coelicolor; D004269:DNA, Bacterial; D036341:Intercellular Signaling Peptides and Proteins; D002686:Chitin; D048271:Chitosan