利用定制的系统和优化的长周期细丝冷冻电镜处理，课题组研究人员确定了来自猪玻璃体的天然胶原原纤维的结构，局部分辨率从2.6到7埃不等。每个67纳米的周期单元包含II型、V/XI型和IX型胶原蛋白三螺旋和光学蛋白，其化学计量比为8:4:4:4，揭示了它们详细的高阶分子排列。丰富的半乳糖-葡萄糖双糖修饰了保守的-甘氨酸- x -羟赖氨酸基序中的羟赖氨酸残基，介导了纤维的堆积和结构稳定性。它们的结构揭示了聚糖介导的胶原原纤维组装原理，阐明了玻璃体中胶原的结构-功能基础。
据了解，胶原蛋白是细胞外基质的基本成分，长期以来一直难以进行高分辨率的结构表征。
附：英文原文
Title: The molecular architecture of mammalian vitreous body collagen fibrils
Author: Xinyao Lou, Ye Cong, Yuqian Xu, Yazhao Liu, Ying Li, Chuangye Yan
Issue&Volume: 2026-07-30
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.
DOI: aec2906
Source: https://www.science.org/doi/10.1126/science.aec2906