Nakai Tomonori, Nishiyama Yoshiharu, Kuga Shigenori, Sugano Yasushi, Shoda Makoto
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
Biochem Biophys Res Commun. 2002 Jul 12;295(2):458-62. doi: 10.1016/s0006-291x(02)00696-4.
An ORF2 gene located upstream of the cellulose synthase (bcs) operon of Acetobacter xylinum BPR2001 was disrupted and a mutant (M2-2) was constructed. In static cultivation, the parent strain produced a tough, colorless, and insoluble cellulose pellicle, whereas M2-2 culture produced a thin, yellow, and fragile pellicle. The results of X-ray diffraction and 13C solid-state NMR indicated that the product of M2-2 is a mixture of cellulose I, cellulose II, and amorphous cellulose. The cellulose I to cellulose II ratio of the mixture was evaluated from the signal areas of C6 to be about 1:2. Electron microscopy revealed that the product of M2-2 included ribbon-like cellulose and irregularly shaped particles attached to the ribbons. On the other hand, the mutant complemented with plasmid pSA-ORF2/k containing the ORF2 gene and BPR2001 produced only cellulose I. These results indicate that the ORF2 gene is involved in the production and crystallization of cellulose I microfibrils by this microorganism.
对木醋杆菌BPR2001纤维素合酶（bcs）操纵子上游的一个开放阅读框2（ORF2）基因进行了破坏，并构建了一个突变体（M2-2）。在静置培养中，亲本菌株产生了坚韧、无色且不溶性的纤维素膜，而M2-2培养物产生了薄的、黄色且易碎的膜。X射线衍射和13C固体核磁共振结果表明，M2-2的产物是纤维素I、纤维素II和无定形纤维素的混合物。从C6的信号区域评估该混合物中纤维素I与纤维素II的比例约为1:2。电子显微镜显示，M2-2的产物包括带状纤维素和附着在带上的不规则形状颗粒。另一方面，用含有ORF2基因的质粒pSA-ORF2/k互补的突变体和BPR2001仅产生纤维素I。这些结果表明，ORF2基因参与了该微生物纤维素I微纤丝的产生和结晶。
