Purification, properties, and partial amino acid sequences of thermostable xylanases from Streptomyces thermoviolaceus OPC-520.
Two types of xylanases (1,4-beta-D-xylan xylanohydrolase, EC 3.2.1.8) were isolated from the culture filtrate of a thermophilic actinomycete, Streptomyces thermoviolaceus OPC-520. The enzymes (STX-I and STX-II) were purified by chromatography with DEAE-Toyopearl 650 M, CM-Toyopearl 650 M, Sephadex G-75, Phenyl-Toyopearl 650 M, and Mono Q HR. The purified enzymes showed single bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weights of STX-I and STX-II were 54,000 and 33,000, respectively. The pIs were 4.2 (STX-I) and 8.0 (STX-II). The optimum pH levels for the activity of STX-I and STX-II were pH 7.0. The optimum temperature for the activity of STX-I was 70 degrees C, and that for the activity of STX-II was 60 degrees C. The enzymes were completely inhibited by N-bromosuccinimide. The enzymes degraded xylan, producing xylose and xylobiose as the predominant products, indicating that they were endoxylanases. STX-I showed high sequence homology with the exoglucanase from Cellulomonas fimi (47% homology), and STX-II showed high sequence homology with the xylanase from Bacillus pumilus (46% homology).
Tsujibo
H
H
Osaka University of Pharmaceutical Sciences, Japan.
Miyamoto
K
K
Kuda
T
T
Minami
K
K
Sakamoto
T
T
Hasegawa
T
T
Inamori
Y
Y
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002854:Chromatography, Paper; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006026:Glycoside Hydrolases / Q000737:chemistry / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment; D013302:Streptomyces / Q000145:classification / Q000201:enzymology*; D013696:Temperature; D043325:Xylan Endo-1,3-beta-Xylosidase
D000596:Amino Acids; D006026:Glycoside Hydrolases; D043325:Xylan Endo-1,3-beta-Xylosidase