Fig. 2: Structure and subcellular localization of CIS^Sc.

a, Representative cryo-electron micrograph of a sheath preparation from WT S. coelicolor that was recorded for structure determination (505 micrographs were collected). All sheath structures were seen in the contracted state. Scale bar, 40 nm. b, Section of the CIS^Sc sheath cryoEM structure in the contracted conformation. Left: side view. Right: top view. c,d, Side view ribbon representation of the Cis2 monomer in its contracted state superposed with the corresponding cryoEM map (c) and with dashed rectangles highlighting the positions of domains 1 (red), 2 (blue) and 3 (orange, not resolved because of high flexibility) (d). e, Representative cryo-electron micrograph of a sheath preparation from S. coelicolor expressing a non-contractile mutant of Cis2 (CIS-N5) (525 micrographs were collected). More than 95% of all structures were seen in the extended state. Scale bar, 40 nm. f, Ribbon representation of a section of the S. coelicolor Cis2 (sheath)-Cis1a (inner tube) cryoEM structure in the extended conformation that was solved using the non-contractile mutant. Left: side view. Right: top view. g,h, Side view ribbon representation of the Cis1a-Cis2 monomer (non-contractile mutant) in its extended state superposed with the corresponding cryoEM map (g) and with dashed rectangles highlighting the positions of domains 1 (red), 2 (blue) and 3 (orange, not resolved because of high flexibility) (h). i, Insights from the cryoEM structures enabled us to tag Cis2 with a fluorescent tag (YPet) for subsequent time-lapse imaging to determine the localization of assembled CIS^Sc. Shown is a still image from Supplementary Video 1 showing scattered fluorescent foci inside vegetative hyphae. White rectangle highlights hypha shown in h. Scale bar, 10 µm. j, Fluorescently tagged CIS^Sc remained largely static or showed short-range movements over time. Shown is an image montage of a representative growing S. coelicolor hypha from Supplementary Video 1. Note that the depicted hypha has been rotated. Images were acquired every 5 min. Scale bar, 10 µm.