Architecture and Assembly of Periplasmic Flagellum.

Periplasmic flagella are complex nanomachines responsible for distinctive morphology and motility of spirochetes. Although bacterial flagella have been extensively studied for several decades in the model systems and , our understanding of periplasmic flagella in many disease-causing spirochetes remains incomplete. Recent advances, including molecular genetics, biochemistry, structural biology, and cryo-electron tomography, have greatly increased our understanding of structure and function of periplasmic flagella. In this chapter, we summarize some of the recent findings that provide new insights into the structure, assembly, and function of periplasmic flagella.