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Structural morphing in a symmetry-mismatched viral vertex.

ABSTRACT: Large biological structures are assembled from smaller, often symmetric, sub-structures. However, asymmetry among sub-structures is fundamentally important for biological function. An extreme form of asymmetry, a 12-fold-symmetric dodecameric portal complex inserted into a 5-fold-symmetric capsid vertex, is found in numerous icosahedral viruses, including tailed bacteriophages, herpesviruses, and archaeal viruses. This vertex is critical for driving capsid assembly, DNA packaging, tail attachment, and genome ejection. Here, we report the near-atomic in situ structure of the symmetry-mismatched portal vertex from bacteriophage T4. Remarkably, the local structure of portal morphs to compensate for symmetry-mismatch, forming similar interactions in different capsid environments while maintaining strict symmetry in the rest of the structure. This creates a unique and unusually dynamic symmetry-mismatched vertex that is central to building an infectious virion.

SUBMITTER: Fang Q

PROVIDER: S-EPMC7136217 | biostudies-literature | 2020 Apr

REPOSITORIES: biostudies-literature

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Structural morphing in a symmetry-mismatched viral vertex.

Fang Qianglin Q Tang Wei-Chun WC Tao Pan P Mahalingam Marthandan M Fokine Andrei A Rossmann Michael G MG Rao Venigalla B VB

Nature communications 20200406 1

Large biological structures are assembled from smaller, often symmetric, sub-structures. However, asymmetry among sub-structures is fundamentally important for biological function. An extreme form of asymmetry, a 12-fold-symmetric dodecameric portal complex inserted into a 5-fold-symmetric capsid vertex, is found in numerous icosahedral viruses, including tailed bacteriophages, herpesviruses, and archaeal viruses. This vertex is critical for driving capsid assembly, DNA packaging, tail attachmen ...[more]

PMID: 32249784

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