A Capsid Structure of Ralstonia solanacearum  podoviridae GP4 with a Triangulation Number T = 9

Viruses. 2022 Nov 1;14(11):2431. doi: 10.3390/v14112431.

Abstract

GP4, a new Ralstonia solanacearum phage, is a short-tailed phage. Few structures of Ralstonia solanacearum phages have been resolved to near-atomic resolution until now. Here, we present a 3.7 Å resolution structure of the GP4 head by cryo-electron microscopy (cryo-EM). The GP4 head contains 540 copies of major capsid protein (MCP) gp2 and 540 copies of cement protein (CP) gp1 arranged in an icosahedral shell with a triangulation number T = 9. The structures of gp2 and gp1 show a canonical HK97-like fold and an Ig-like fold, respectively. The trimeric CPs stick on the surface of the head along the quasi-threefold axis of the icosahedron generating a sandwiched three-layer electrostatic complementary potential, thereby enhancing the head stability. The assembly pattern of the GP4 head provides a platform for the further exploration of the interaction between Ralstonia solanacearum and corresponding phages.

Keywords: Cryo-EM; Ralstonia solanacearum phage; icosahedral head; triangulation number T = 9; trimeric CP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriophages* / genetics
  • Capsid / chemistry
  • Capsid Proteins / chemistry
  • Cryoelectron Microscopy
  • Podoviridae*
  • Ralstonia solanacearum*

Substances

  • Capsid Proteins
  • GP 4

Grants and funding

This research was supported by the National Natural Science Foundation of China (12034006, 32071209, 32200994, and 31971122), the Natural Science Foundation of Hunan Province, China (2020JJ2015), the China Postdoctoral Science Foundation (2021TQ0104 and 2022M711127).