纤维素体是一种高效的纤维素分解复合物,含有纤维素分解酶和非催化亚基,即支架,通过酶的dockerin模块和主要支架的cohesin模块之间的相互作用组装。纤维素体通过锚定支架的S层同源性(SLH)模块附着到细胞表面。热纤梭菌DSM1313是一种嗜热纤维素体产生细菌,在木质纤维素生物转化和生物燃料生产中具有巨大潜力。该细菌含有四种固定支架ScaB,Scac,ScaD和ScaF,其中ScaF是唯一一个在cohesin和SLH模块之间包含未知函数的附加模块(ScaF-X)的模块。ScaF基因位于scaA的支架蛋白基因簇之外,scaB,scaC和scaD。先前的研究表明,与其他锚固支架相比,ScaF具有独特的调节特性和功能,这可能与附加的ScaF-X模块有关。在这里,我们报告了来自C.热纤DSM1313的ScaF-X的NMR化学位移分配。良好分散的NMR光谱和基于ScaF-X化学位移的二级结构预测表明ScaF-X是折叠良好的蛋白质模块。化学位移分配为进一步研究该模块的结构及其在纤维素体中的功能提供了基础。
The cellulosome is a highly efficient cellulolytic complex containing cellulolytic enzymes and non-catalytic subunits, i.e. scaffoldins, which are assembled by the interactions between the dockerin modules of the enzymes and the cohesin modules of the primary scaffoldins. The cellulosome attaches to the cell surface via the S-layer homology (SLH) modules of the anchoring scaffoldins. Clostridium thermocellum DSM1313 is a thermophilic cellulosome-producing bacterium with great potential in lignocellulose bioconversion and biofuel production. The bacterium contains four anchoring scaffoldins ScaB, ScaC, ScaD and ScaF, among which ScaF is the only one that contains an additional module of unknown function (ScaF-X) between the cohesin and SLH modules. The gene of ScaF is located outside the scaffoldin gene cluster of scaA, scaB, scaC and scaD. Previous studies showed unique regulation properties and function of ScaF compared to other anchoring scaffoldins, which might be related to the additional ScaF-X module. Here we report the NMR chemical shift assignments of ScaF-X from C. thermocellum DSM1313. The well-dispersed NMR spectrum and the secondary structure prediction based on the chemical shifts of ScaF-X indicated that ScaF-X is a well-folded protein module. The chemical shift assignments provide the basis for future studies on the structure of this module and its function in cellulosomes.