ジャーナル: Nat Commun / 年: 2019 タイトル: Principles for enhancing virus capsid capacity and stability from a thermophilic virus capsid structure. 著者: Nicholas P Stone / Gabriel Demo / Emily Agnello / Brian A Kelch / 要旨: The capsids of double-stranded DNA viruses protect the viral genome from the harsh extracellular environment, while maintaining stability against the high internal pressure of packaged DNA. To ...The capsids of double-stranded DNA viruses protect the viral genome from the harsh extracellular environment, while maintaining stability against the high internal pressure of packaged DNA. To elucidate how capsids maintain stability in an extreme environment, we use cryoelectron microscopy to determine the capsid structure of thermostable phage P74-26 to 2.8-Å resolution. We find P74-26 capsids exhibit an overall architecture very similar to those of other tailed bacteriophages, allowing us to directly compare structures to derive the structural basis for enhanced stability. Our structure reveals lasso-like interactions that appear to function like catch bonds. This architecture allows the capsid to expand during genome packaging, yet maintain structural stability. The P74-26 capsid has T = 7 geometry despite being twice as large as mesophilic homologs. Capsid capacity is increased with a larger, flatter major capsid protein. Given these results, we predict decreased icosahedral complexity (i.e. T ≤ 7) leads to a more stable capsid assembly.
A: Major head protein B: Major head protein C: Major head protein D: Major head protein E: Major head protein F: Major head protein G: Major head protein H: P74-26 Head Decoration Protein I: P74-26 Head Decoration Protein J: P74-26 Head Decoration Protein K: P74-26 Head Decoration Protein L: P74-26 Head Decoration Protein M: P74-26 Head Decoration Protein N: P74-26 Head Decoration Protein
A: Major head protein B: Major head protein C: Major head protein D: Major head protein E: Major head protein F: Major head protein G: Major head protein H: P74-26 Head Decoration Protein I: P74-26 Head Decoration Protein J: P74-26 Head Decoration Protein K: P74-26 Head Decoration Protein L: P74-26 Head Decoration Protein M: P74-26 Head Decoration Protein N: P74-26 Head Decoration Protein
x 60
complete icosahedral assembly
根拠: microscopy, Assembly constructed using icosahedral cryoEM reconstruction
A: Major head protein B: Major head protein C: Major head protein D: Major head protein E: Major head protein F: Major head protein G: Major head protein H: P74-26 Head Decoration Protein I: P74-26 Head Decoration Protein J: P74-26 Head Decoration Protein K: P74-26 Head Decoration Protein L: P74-26 Head Decoration Protein M: P74-26 Head Decoration Protein N: P74-26 Head Decoration Protein
x 5
icosahedral pentamer
2.21 MDa, 70 ポリマー
分子量 (理論値)
分子数
合計 (水以外)
2,207,008
70
ポリマ-
2,207,008
70
非ポリマー
0
0
水
0
タイプ
名称
対称操作
数
identity operation
1_555
x,y,z
1
point symmetry operation
4
4
A: Major head protein B: Major head protein C: Major head protein D: Major head protein E: Major head protein F: Major head protein G: Major head protein H: P74-26 Head Decoration Protein I: P74-26 Head Decoration Protein J: P74-26 Head Decoration Protein K: P74-26 Head Decoration Protein L: P74-26 Head Decoration Protein M: P74-26 Head Decoration Protein N: P74-26 Head Decoration Protein