||Bacteria Escherichia coli
||Neidhardt F.C. Escherichia coli and Salmonella: Cellular and Molecular Biology. Vol 1. p. 147, ASM Press 1996 chapter 10- Flagella and motility p.2 2nd paragraph
|| Namba K, Yamashita I, Vonderviszt F. Structure of the core and central channel of bacterial flagella. Nature. 1989 Dec 7 342(6250):648-54.PubMed ID2687696
||Primary source abstract: "X-ray fibre diffraction analysis"
||P.2 2nd paragraph: "Geometrical, Biochemical, and Mechanical Properties: The filament is of variable length (typically 5 to 10 µm) but has a constant diameter of about 20 nm throughout its length (primary source). It is macroscopically helical (corkscrew-like), with helical parameters that vary slightly between the two species [E. coli and S. typhimurium] and even among strains: typical values are 2 to 2.5 μm for the helical wavelength (pitch) and 0.4 to 0.6 μm for the helical diameter (ref 85). For any given filament, these values are constant throughout its length: in other words, the structure has a strictly conserved geometry and may be regarded as a unidimensional crystal."
||Ron Milo, Paul Jorgensen, Mike Springer