Flagellar structure

Huang, B. (1986). Chlamydomonas reinhardtii. A model system for genetic analysis of flagellar structure and motility. Inti. Rev. Cytol. 99, 181-215. 

Apart from the kinds of publications as given in fig. 5, there are also reports on the study of only one character complex, e.g. alkaloid pattern, vascular system, flagellar structure. We are then at the boundary between systematics and another discipline, e.g. organic... 

Doetsch, R.N. and Sjoblad, R.D. (1980). Flagellar structure and function in eubac-teria. Annu. Rev. Microbiol. 34, 69-108. 

The stepwise assembly process of the flagellum has been concluded from incomplete flagellar structures produced by flagellar mutants [325, 387, 713, 714]. This sequence of steps was recently confirmed by realtime monitoring of the transcriptional activation of the flagellar operons by means of a panel of 14 reporter plasmids in which green-fluorescent... 

Suzuki, T, lino, T, Horiguchi, T. and Yamaguchi, S. (1978). Incomplete flagellar structures in nonflagellate mutants of Salmonella typhimurium. J. Bacterial. 133, 904-915. 

Suzuki, T. and Komeda, Y. (1981). Incomplete flagellar structure in Escherichia coli mutants./. Bacterial. 145, 1036-1041. 

Figure 2. A three-dimensional reconstitution of the flagellar structure. Red, peripheral microtubule doublets orange, central microtubule singlets purple, nexin bridges blue, outer dynein arms yellow, inner dynein arms green, radial spokes. (Kindly provided by Dr Jacky Cosson, CNRS, France.]...

The biflagellate unicellular green alga Chlamydomonas reinhardtii is prone to spontaneous mutations that produce deficiencies in flagellar proteins and MT assembly, substructure, and function. Viable mutants that are either nonmotile or slow moving can be isolated and analyzed biochemically and morphologically, thereby establishing structure-function correlations. Electron microscopic analysis... 

Yang, Z., Kollman, J. M., Pandi, L., and Doolittle, R. F. (2001). Crystal structure of native chicken fibrinogen at 2.7 A resolution. Biochemistry 40, 12515-12523. Yonekura, K., Maki-Yonekura, S., and Namba, K. (2003). Complete atomic model of the bacterial flagellar filament by electron cryomicroscopy. Nature 424, 643-650. Zhang, L., and Hermans, J. (1993). Calculation of the pitch of the a-helical coiled coil An addendum. Proteins 17, 217-218. 

Suzuki, H., Yonekura, K., and Namba, K. (2004). Structure of the rotor of the bacterial flagellar motor revealed by electron cryomicroscopy and single-particle image analysis./. Mol. Biol. 337, 105-113. 

When microtubules were visualized by electron microscopy (EM), after the improvement of methods of fixation, it was realized that they formed the structural basis of flagellar axonemes and of so-called spindle fibers, as well as occurring as individual filaments in the cytoplasm. Their designation as part of the cytoskeleton suggested that they acted mainly as fixed structural supports. Subsequent research has focused more and more on their dynamic behavior and on their role as tracks for motor proteins, which may, for example, transport chromosomes during cell division. Microtubules are found in all eukaryotic cells and are essential for many cellular functions, such as motility, morphogenesis, intracellular transport, and cell division. It is that dynamic behavior that allows microtubules to fulfill all of these functions in specific places and at appropriate times in the cell cycle. 

Figure 6.1 shows the structure of the flagellar motor in a simple illustration that reminds us of artificial machines. This machine-like motor is constructed through the self-assembly of proteins. The superior fimctionality and complexity of biological super molecules is quite apparent from this example. The energy for the rotation of the motor is provided by a proton flow from the outside to the inside of the bacteria. When an electrical potential difference is applied between the outside and the inside of the bacteria by immobilizing the bacterial cell on micropipette, the rotation speed can be controlled by al-... 

N.R. Francis, G.E. Sosinsky, D. Thomas, D.J. Derosier, Isolation, Characterization and Structure of Bacterial, Flagellar, Motors Containing the Switch Complex , J. Mol. Biol., 235, 1261 (1994)... 

Figure 34.30. Flagellar Motor. A schematic vieve of the flagellar motor, a complex structure containing as many as 40 distinct types of protein. The approximate positions of the proteins MotA and MotB (red), FliG (orange), FliN (yellow), and FliM (green) are shown.

Figure 34.31. Flagellar Motor Components. Approximately 30 subunits of FliG assemble to form part of the MS ring. The ring is surrounded by approximately 11 structures consisting of MotA and MotB. The carboxyl-terminal domain of FliG includes a ridge lined with charged residues that may participate in proton transport.

Backward rotation. On the basis of the proposed structure in Figure 34,32 for the bacterial flagellar motor, suggest a pathway for transmembrane proton flow when the flagellar motor is rotating clockwise rather than counterclockwise. 

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