27WR

horse myoglobin amyloid fibril - PM1

Summary for 27WR

• Entry DOI: 10.2210/pdb27wr/pdb
• EMDB information: 81518
• Descriptor: Myoglobin (1 entity in total)
• Functional Keywords: protein fibril
• Biological source: Equus caballus (horse)
• Total number of polymer chains: 10
• Total formula weight: 31485.49

Authors

Li, S.,Cao, Q.,Cao, Y. (deposition date: 2026-06-15, release date: 2026-07-22, Last modification date: 2026-07-29)

Primary citation

Li, S.,Li, S.,Zhao, Y.,Fang, Y.,Cao, Q.,Cao, Y.
Myoglobin Amyloid Fibrils Reveal a Hierarchical Principle of Polymorphism and Electrostatic Self-Assembly.
Nano Lett., 26:8827-8833, 2026

PubMed Abstract: The atomic architecture of apomyoglobin amyloid fibrils, despite the protein's dual distinction as the first structurally resolved protein and the paradigmatic nondisease amyloid, has remained a decades-long puzzle. Here, we identify electrostatic screening as the critical switch that enables the formation of highly ordered apomyoglobin fibrils, allowing us to determine the cryo-electron microscopy structures of three distinct polymorphs (PM1, PM2, and PM3) at 2.7 Å resolution. The structures reveal a conserved "hydrophobic-in, positively charged-out" architecture, where a charged surface surrounds a tightly packed core, providing a structural explanation for salt-dependent assembly. Structural comparisons reveal a hierarchical principle of amyloid organization, in which short sequence segments retain conserved local conformations dictated by their intrinsic folding propensities, while variations in supramolecular packing give rise to polymorphic diversity. These findings establish a molecular framework for understanding electrostatically controlled self-assembly and the structural basis of amyloid polymorphism.

PubMed: 42378159
DOI: 10.1021/acs.nanolett.6c02104

Experimental method

ELECTRON MICROSCOPY (2.7 Å)