Okamoto Shinobu, Ohmori Masayuki
Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro, Tokyo, 153-8902 Japan.
Plant Cell Physiol. 2002 Oct;43(10):1127-36. doi: 10.1093/pcp/pcf128.
The unicellular cyanobacterium, Synechocystis sp. PCC 6803 is motile. A homologue of the PilT protein family, required for twitching motility in Pseudomonas aeruginosa and social gliding motility in Myxococcus xanthus, was found to be necessarily associated with cyanobacterial motility. The pilT1 (slr0161) mutant shows a pleotropic phenotype, defects in individual cell motility, and an increased number of long surface pili. Furthermore, the mutant loses its ability of natural competency. These findings demonstrate that PilT1 is essential for both cell motility and competency. Since the pilT gene contains a consensus ATP-binding motif (Walker boxes), the PilT protein is suggested for supplying energy for cell motility. The product of pilT1, overproduced in Escherichia coli and purified by Ni-affinity chromatography, hydrolyzes ATP in vitro.
单细胞蓝细菌集胞藻6803具有运动能力。人们发现，铜绿假单胞菌的颤动运动以及黄色黏球菌的群体滑动运动所需的PilT蛋白家族的一个同源物，必然与蓝细菌的运动有关。pilT1（slr0161）突变体表现出多效性表型、单个细胞运动缺陷以及长表面菌毛数量增加。此外，该突变体丧失了自然感受态能力。这些发现表明，PilT1对于细胞运动和感受态都是必不可少的。由于pilT基因包含一个共有ATP结合基序（沃克框），因此推测PilT蛋白为细胞运动提供能量。pilT1的产物在大肠杆菌中过量表达并通过镍亲和层析纯化，在体外可水解ATP。
