Kang Seungha, Barak Yoav, Lamed Raphael, Bayer Edward A, Morrison Mark
The MAPLE Research Initiative, Department of Animal Sciences, The Ohio State University, Columbus, OH, USA.
Mol Microbiol. 2006 Jun;60(6):1344-54. doi: 10.1111/j.1365-2958.2006.05182.x.
Many of the Firmicutes bacteria responsible for plant polysaccharide degradation in Nature produce a multiprotein complex called a cellulosome, which co-ordinates glycoside hydrolase assembly, bacterial adhesion to substrate and polysaccharide hydrolysis. Cellulosomal proteins possess a dockerin module, which mediates their attachment to the scaffoldin protein via its interaction with cohesin modules, and only glycoside hydrolases and other carbohydrate active enzymes were known to reside within the cellulosome. We show here with Clostridium thermocellum ATCC 27405 that members of the serpin superfamily of serine proteinase inhibitors, which are best recognized for their conformational flexibility and co-ordination of key regulatory functions in multicellular eukaryotes, also reside within the cellulosome. These studies are the first to expand the cellulosome paradigm of protein complex assembly beyond glycoside hydrolase and carbohydrate active enzymes, and to include a newly identified functionality in the Firmicutes.
自然界中许多负责降解植物多糖的厚壁菌会产生一种名为纤维小体的多蛋白复合物，该复合物可协调糖苷水解酶组装、细菌与底物的黏附以及多糖水解。纤维小体蛋白具有一个dockerin模块，它通过与黏连蛋白模块相互作用介导自身与支架蛋白的附着，并且已知只有糖苷水解酶和其他碳水化合物活性酶存在于纤维小体中。我们在此利用嗜热栖热菌ATCC 27405表明，丝氨酸蛋白酶抑制剂丝氨酸蛋白酶抑制剂超家族的成员，因其构象灵活性以及在多细胞真核生物中关键调节功能的协调作用而最为人所知，也存在于纤维小体中。这些研究首次将蛋白质复合物组装的纤维小体模式扩展到糖苷水解酶和碳水化合物活性酶之外，并在厚壁菌中纳入了新发现的功能。
