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Multiple nanocages of a cyanophage small heat shock protein with icosahedral and octahedral symmetries.

ABSTRACT: The structures of a cyanophage small heat shock protein (sHSP) were determined as octahedrons of 24-mers and 48-mers and as icosahedrons of 60-mers. An N-terminal deletion construct of an 18 kDa sHSP of Synechococcus sp. phage S-ShM2 crystallized as a 24-mer and its structure was determined at a resolution of 7 Å. The negative stain electron microscopy (EM) images showed that the full-length protein is a mixture of a major population of larger and a minor population of smaller cage-like particles. Their structures have been determined by electron cryomicroscopy 3D image reconstruction at a resolution of 8 Å. The larger particles are 60-mers with icosahedral symmetry and the smaller ones are 48-mers with octahedral symmetry. These structures are the first of the viral/phage origin and the 60-mer is the largest and the first icosahedral assembly to be reported for sHSPs.

SUBMITTER: Biswas S

PROVIDER: S-EPMC8546028 | biostudies-literature | 2021 Oct

REPOSITORIES: biostudies-literature

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Multiple nanocages of a cyanophage small heat shock protein with icosahedral and octahedral symmetries.

Biswas Sreeparna S Garg Priyanka P Dutta Somnath S Suguna Kaza K

Scientific reports 20211025 1

The structures of a cyanophage small heat shock protein (sHSP) were determined as octahedrons of 24-mers and 48-mers and as icosahedrons of 60-mers. An N-terminal deletion construct of an 18 kDa sHSP of Synechococcus sp. phage S-ShM2 crystallized as a 24-mer and its structure was determined at a resolution of 7 Å. The negative stain electron microscopy (EM) images showed that the full-length protein is a mixture of a major population of larger and a minor population of smaller cage-like particle ...[more]

PMID: 34697325

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