AFM study of potato virus X disassembly induced by movement protein

J Mol Biol. 2003 Sep 12;332(2):321-5. doi: 10.1016/s0022-2836(03)00835-0.


Recently we have reported that a selective binding of potato virus X (PVX)-coded movement protein (termed TGBp1 MP) to one end of a polar coat protein (CP) helix converted viral RNA into a translatable form and induced a linear destabilization of the whole helical particle. Here, the native PVX virions, RNase-treated (PVX(RNA-DEG)) helical particles lacking intact RNA and their complexes with TGBp1 (TGBp1-PVX and TGBp1-PVX(RNA-DEG)), were examined by atomic force microscopy (AFM). When complexes of the TGBp1 MP with PVX were examined by means of AFM in liquid, no structural reorganization of PVX particles was observed. By contrast, the products of TGBp1-dependent PVX degradation termed "beads-on-string" were formed under conditions of AFM in air. The AFM images of PVX(RNA-DEG) were indistinguishable from images of native PVX particles; however, the TGBp1-dependent disassembly of the CP-helix was triggered when the TGBp1-PVX(RNA-DEG) complexes were examined by AFM, regardless of the conditions used (in air or in liquid). Our data supported the idea that binding of TGBp1 to one end of the PVX CP-helix induced linear destabilization of the whole helical particle, which may lead to its disassembly under conditions of AFM.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Capsid Proteins / chemistry*
  • Capsid Proteins / metabolism
  • Capsid Proteins / ultrastructure
  • Macromolecular Substances
  • Microscopy, Atomic Force
  • Plant Viral Movement Proteins
  • Potexvirus / chemistry*
  • Potexvirus / metabolism
  • Protein Binding
  • Protein Conformation*
  • RNA, Viral
  • Viral Proteins / chemistry*
  • Viral Proteins / metabolism
  • Viral Proteins / ultrastructure
  • Virion / genetics
  • Virion / metabolism


  • Capsid Proteins
  • Macromolecular Substances
  • Plant Viral Movement Proteins
  • RNA, Viral
  • Viral Proteins