| Research Abstract |
Mycoplasma (Mycoplasma mobile), a wall-less prokaryote has flask-shaped cell morphology. It binds to a glass surface by the tapered end and glides with keeping binding. The speed and the maximal force reach up to 2.5 micrometer per second (4 times of cell length) and 27 piconewtons, respectively. However, mycoplasma does not have any flagella or pili which are commonly found in other motile bacteria, moreover any motor proteins such as myosin commonly found in eukaryotic cell motility. Therefore, this motility mechanism cannot be explained by today's biology. This study has been done to elucidate this unknown mechanism and clarified the following facts.
1.Two proteins are responsible for gliding motility, which are featured with very large molecular weights, 349 and 521 kDa, respectivly, and special structures. We named them as Gli349 and Gli521.
2.Gli349 is responsible for glass binding during gliding, and Gli521 is responsible for force generation.
3.Those gliding proteins are localized all around the neck, the base of membrane protrusion.
4.The gliding machinery observed by rapid-freeze-and-fracture rotary shadow electron microscopy method was a 50-nm long spike structure sticking out from the membrane.
5.The purified Gli349 protein molecule is a music note-like structure with 115-nm total length.
6.The above results can be explained by an assumption that Gli349 moved by Gli521 thrusts a cell by repeating association and dissociation with glass.
|
