Subunit composition of a large xylanolytic complex (xylanosome) from Streptomyces olivaceoviridis E-86.
A xylanolytic complex (xylanosome) was isolated from Streptomyces olivaceoviridis E-86 grown on corncob xylan. The isolated xylanosome exhibited a high molecular mass of approximately 3.8 x 10(7) Da (weight average) using size exclusion chromatography/multi-angle laser light scattering (SEC/MALLS), and was composed of at least 8 subunits with a mass range from 12 to 60 kDa. When a SDS-polyacrylamide gel zymogram was examined, the subunits of 47, 35, 32, and 23 kDa were found to have xylanase activity, while the 30-kDa subunit had CMCase activity. According to N-terminal sequence analyses, the 47- and 23-kDa subunits were found to be identical to the two reported xylanases, namely FXYN and GXYN, of S. olivaceoviridis E-86. Both the 35- and 32-kDa subunits were found to be truncated forms of the intact FXYN xylanase that possibly resulted from the degradation by proteases. The 15-kDa subunit consisted solely the xylan-binding domain of the FXYN xylanase. The purified xylanosome appeared to bind partially to xylan and poorly to Avicel.
Jiang
Zhengqiang
Z
Department of Biotechnology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China. zhqjiang@cau.edu.cn
Dang
Wei
W
Yan
Qiaojuan
Q
Zhai
Qian
Q
Li
Lite
L
Kusakabe
Isao
I
D002482:Cellulose / Q000737:chemistry*; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry*; D008970:Molecular Weight; D021122:Protein Subunits; D013302:Streptomyces / Q000201:enzymology*; D014990:Xylans / Q000737:chemistry*
D021122:Protein Subunits; D014990:Xylans; D002482:Cellulose; D043364:Endo-1,4-beta Xylanases