解纤维梭菌纤维小体黏附域与锚定域相互作用的差异性

Differences in the Interaction Between the Cellulosome Cohesin Domain and Dockerin Domain of Ruminiclostridium Cellulolyticum

黏附域(cohesin)与锚定域(dockerin)的相互作用是纤维素酶复合体-纤维小体(cellulosome)组装的基础,该作用是自然界已知最强的相互作用力之一。为解析纤维小体的装配机制,本研究以解纤维梭菌(Ruminiclostridium cellulolyticum)纤维小体为研究对象,通过Pull-down和等温滴定量热(ITC)的方法,分析并比较不同簇的3个黏附域与7个锚定域之间的相互作用。结果表明,不同簇黏附域与锚定域的相互作用具有显著差异。其中,Coh1与Doc-0729的相互作用最强,Ka为108 M-1,Coh7与Doc-0729、0931作用力强,Ka为107 M-1,而Coh8与Doc-0931、1656、0752作用强,Ka也达到107 M-1。总之,Doc-0729、0931、1656与3个Coh的结合力均较高。本研究揭示了纤维小体黏附域与锚定域的组装具有偏爱性,这为人工纤维小体的设计和装配奠定了理论基础。

Cohesin-dockerin interaction is fundamental to the assembly of the cellulosome complex and is one of the strongest non-covalent interactions known in nature. In this study, the differences of interactions between three cohesins and seven dockerins were analyzed to clarify the assembly mechanism of the cellulosome from mesophilic anaerobic Ruminiclostridium cellulolyticum. The results of pull-down and isothermal titration calorimetry(ITC) showed that the interaction strength of Coh1 was the highest with Doc-0729 with a binding constant Kavalue of 10~8 M-1. And Coh7 is the highest with Doc-0729 and 0931 with the Kavalue of 107M-1, while Coh8 has the strongest interaction with Doc-0931, 1656 and 0752, with the Kavalue of 10~7 M-1, suggesting that the significant difference of the interaction between cohesins and dockerins. This finding reveals the preference for the assembly of the cohesin and dockerin of the cellulosome, which lays a theoretical foundation for the design and assembly of the artificial cellulosome.