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Updated: Aug 5, 2026

Preparing Porcine Eyes for Confocal Reflectance Microscopy to Visualize the Vitreous Collagen Fiber Network
Published on: October 17, 2025
The molecular architecture of mammalian vitreous body collagen fibrils
Xinyao Lou1, Ye Cong1, Yuqian Xu1
1State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structures, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
Abstract:
Collagen, a fundamental constituent of the extracellular matrix, has long remained elusive to high-resolution structural characterization. Using a tailored system and optimized cryo-electron microscopy processing for long-period filaments, we determined the structure of native collagen fibrils from the porcine vitreous body, with local resolutions extending from 2.6 to 7 angstroms. Each 67-nanometer periodic unit contains type II, V/XI, and IX collagen triple helices together with opticin, at a stoichiometry of 8:4:4:4, which reveals their detailed higher-order molecular packing. Abundant galactose-glucose disaccharides modify hydroxylysine residues in conserved -glycine-X-hydroxylysine- motifs, mediating fibril packing and structural stability. Our structure uncovers the glycan-mediated assembly principle of collagen fibrils and clarifies the structure-function basis of collagens in the vitreous body.
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