Cellulose promotes extracellular assembly of Clostridium cellulovorans cellulosomes
Cellulose promotes extracellular assembly of Clostridium cellulovorans cellulosomes
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DOI：
10.1128/jb.176.22.6952-6956.1994
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发表时间：
1994-11
影响因子：
3.2
通讯作者：
Y. Matano;J. S. Park;M. Goldstein;R. Doi
中科院分区：
文献类型：
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作者：
Y. Matano;J. S. Park;M. Goldstein;R. Doi
通过在含有不同碳源的培养基中生长细胞来研究由食纤维梭菌合成纤维素体。与纤维二糖一起生长的细胞的上清液不含纤维素体，仅含游离形式的纤维素体主要亚基CbpA、P100和P70以及具有酶活性的次要亚基。来自在球磨纤维素和Avicel上生长的细胞的上清液含有能够降解结晶纤维素的纤维素体。与纤维二糖、球磨纤维素和Avicel一起生长的细胞的上清液含有大约相同量的羧甲基纤维素酶活性。尽管来自含有纤维二糖的培养基的上清液最初不含有活性纤维素体，但向无细胞上清液级分中加入结晶纤维素将游离主要形式转化为具有降解结晶纤维素能力的纤维素体。P100和P70与结晶纤维素的结合依赖于它们与CbpA的内切葡聚糖酶结合结构域的连接。这些数据有力地表明，结晶纤维素促进纤维素体组装。
Cellulosome synthesis by Clostridium cellulovorans was investigated by growing the cells in media containing different carbon sources. Supernatant from cells grown with cellobiose contained no cellulosomes and only the free forms of cellulosomal major subunits CbpA, P100, and P70 and the minor subunits with enzymatic activity. Supernatant from cells grown on pebble-milled cellulose and Avicel contained cellulosomes capable of degrading crystalline cellulose. Supernatants from cells grown with cellobiose, pebble-milled cellulose, and Avicel contained about the same amount of carboxymethyl cellulase activity. Although the supernatant from the medium containing cellobiose did not initially contain active cellulosomes, the addition of crystalline cellulose to the cell-free supernatant fraction converted the free major forms to cellulosomes with the ability to degrade crystalline cellulose. The binding of P100 and P70 to crystalline cellulose was dependent on their attachment to the endoglucanase-binding domains of CbpA. These data strongly indicate that crystalline cellulose promotes cellulosome assembly.