Imaging flagella of halobacteria by atomic force microscopy

Abstract

Halobacterial flagella were adsorbed on mica and imaged with an atomic force microscope in air. Different assemblies such as large, net-like structures, and straight flagella aligned by flow were observed. The hypothesis of individual flagellar motors was confirmed by frequent observation of knobs at the end of single flagella. A periodic substructure was observed along flagellar strands with a spacing of 50–100 nm. The diameter of halobacterial flagella was determined as 11 ± 4 nm. The influence of two different preparations on the flagellar profile, and reasons for the distortion of height and width are discussed.