The Cyanobacterial PilT Protein Responsible for Cell Motility and Transformation Hydrolyzes ATP

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.