Sand Andy, Holwerda Evert K, Ruppertsberger Natalie M, Maloney Marybeth, Olson Daniel G, Nataf Yakir, Borovok Ilya, Sonenshein Abraham L, Bayer Edward A, Lamed Raphael, Lynd Lee R, Shoham Yuval
Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Thayer School of Engineering at Dartmouth College, Hanover, NH 03755, United States.
FEBS Lett. 2015 Oct 7;589(20 Pt B):3133-40. doi: 10.1016/j.febslet.2015.08.026. Epub 2015 Aug 29.
Clostridium thermocellum efficiently degrades crystalline cellulose by a high molecular weight protein complex, the cellulosome. The bacterium regulates its cellulosomal genes using a unique extracellular biomass-sensing mechanism that involves alternative sigma factors and extracellular carbohydrate-binding modules attached to intracellular anti-sigma domains. In this study, we identified three cellulosomal xylanase genes that are regulated by the σ(I6)/RsgI6 system by utilizing sigI6 and rsgI6 knockout mutants together with primer extension analysis. Our results indicate that cellulosomal genes are expressed from both alternative σ(I6) and σ(A) vegetative promoters.
嗜热栖热梭菌通过一种高分子量蛋白质复合物——纤维小体高效降解结晶纤维素。该细菌利用一种独特的细胞外生物质传感机制来调控其纤维小体基因，这种机制涉及替代σ因子以及附着于细胞内抗σ结构域的细胞外碳水化合物结合模块。在本研究中，我们通过使用sigI6和rsgI6基因敲除突变体并结合引物延伸分析，鉴定出了三个受σ(I6)/RsgI6系统调控的纤维小体木聚糖酶基因。我们的结果表明，纤维小体基因由替代σ(I6)和σ(A)营养启动子共同表达。
