Studying bacterial chemosensory array with CryoEM

Abstract

Bacteria direct their movement in respond to gradients of nutrients and other stimuli in the environment through the chemosensory system. The behavior is mediated by chemosensory arrays that are made up of thousands of proteins to form an organized array near the cell pole. In this review, we briefly introduce the architecture and function of the chemosensory array and its core signaling unit. We describe the in vivo and in vitro systems that have been used for structural studies of chemosensory array by cryoEM, including reconstituted lipid nanodiscs, 2D lipid monolayer arrays, lysed bacterial ghosts, bacterial minicells and native bacteria cells. Lastly, we review recent advances in structural analysis of chemosensory arrays using state-of-the-art cryoEM and cryoET methodologies, focusing on the latest developments and insights with a perspective on current challenges and future directions.

Methods to Evaluate Bacterial Motility and Its Role in Bacterial–Host Interactions

“…Common techniques for visualizing nanomachineries include electron microscopy (EM) and its variations: transmission EM, scanning EM, and cryo-EM [ 68 ] are used to observe and study the structure of these bacterial components. Specifically, cryo-EM has recently provided 3D structural models of motility- [ 4 ] and chemotaxis-related [ 69 ] components with high resolution. However, freezing the cell makes capturing the dynamics of the machinery unachievable.…”