Refined Mechanism of Mycoplasma mobile Gliding Based on Structure, ATPase Activity, and Sialic Acid Binding of Machinery

Abstract

The genus Mycoplasma is made up of the smallest parasitic and sometimes commensal bacteria; Mycoplasma pneumoniae , which causes human “walking pneumonia,” is representative. More than ten Mycoplasma species glide on host tissues by novel mechanisms, always in the direction of the distal side of the machinery. Mycoplasma mobile , the fastest species in the genus, catches, pulls, and releases sialylated oligosaccharides (SOs), the carbohydrate molecules also targeted by influenza viruses, by means of a specific receptor and using ATP hydrolysis for energy. Here, the architecture of the gliding machinery was visualized three dimensionally by electron cryotomography (ECT), and changes in the structure and binding activity coupled to ATP hydrolysis were discovered. Based on the results, a refined mechanism was proposed for this unique motility.