Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2023 Mar 30;14:1775. doi: 10.1038/s41467-023-37327-w

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© The Author(s) 2023

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

PMC Copyright notice

Fig. 4 — a, b Cross-sectional tomographic slices of the averaged 8-nm repeats of the CF fibers in the protruded (a) and retracted (b) states. c–e The high-resolution structure of tubulin was fitted into the subtomogram averages of the protruded (c, blue) and the retracted (d, pink) states. Comparison (e) of the two pseudo-atomic protofilament models in the protruded (blue) and retracted (pink) states shows no significant difference. f Longitudinal views of the pseudo-atomic protofilament model in the retracted state. The pitch was estimated based on the rise of the periodic CF-associated MAPs between neighboring protofilaments. g Isosurface rendering of the nice-fold averaged protofilaments display a “clockwise skew” when viewed from the conoid base, suggesting the minus ends of the conoid fibers are orientated to the base. h The arrangements of the modeled protofilaments in the CFs (pink) compared with the high-resolution cryo-EM structure of the typical 13-protofilament subpellicular microtubules (green; EMDB: EMD-23870). The most substantial difference is the angle change between PF4 and PF5, causing a tight kink in the protofilament arrangement. i–k Tomographic slices of the global CF subtomogram averages that combine all data from both the protruded (a) and retracted (b) states viewed in cross-sectional (i: original; i’: pseudo-colored) and longitudinal (j and k) orientations. The white lines in (i) indicate the locations of the slices in the respective panels. Labels and coloring see below. l–o Isosurface renderings show the 3D structures of the averaged CF repeats in cross-sectional (l) and longitudinal (m) views, as well as the CFs from a complete conoid (n) by assembling the averaged 8-nm repeats back into the full tomogram. This and the zoom-in (o) show that the open face of the C-shaped CFs faces the interior of the conoid. Labels and coloring: 1–9, protofilaments; IA (blue) and OA (pink) “inner-layer arm” and “outer-layer arm” densities, IJ (yellow) inner junction, MAP; MAP1 (orange), MAP2 (magenta), MAP4 (green), microtubule-associated proteins. Scale bars: 10 nm (in a, b, i–k).