title: Subunit composition of a large xylanolytic complex (xylanosome) from Streptomyces olivaceoviridis E-86.
abstract: 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.
authors.affiliation: Department of Biotechnology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China. zhqjiang@cau.edu.cn
authors.forename: Zhengqiang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Dang
authors.forename: Qiaojuan
authors.initials: Q
authors.lastname: Yan
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhai
authors.forename: Lite
authors.initials: L
authors.lastname: Li
authors.forename: Isao
authors.initials: I
authors.lastname: Kusakabe
mesh_terms: 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*
chemical_list: D021122:Protein Subunits; D014990:Xylans; D002482:Cellulose; D043364:Endo-1,4-beta Xylanases