Tomato bushy stunt virus at 2.9 A resolution

Area of Science:

• Structural biology
• Virology
• Biochemistry

Background:

• Tomato Bushy Stunt Virus (TBSV) is an important plant pathogen.
• Understanding the structural organization of viral proteins is crucial for deciphering viral assembly and function.

Purpose of the Study:

• To elucidate the three-dimensional structure and quaternary organization of TBSV subunits.
• To investigate the role of N-terminal arms in protein-protein interactions within the viral capsid.

Main Methods:

• Analysis of the polypeptide chain folding into distinct domains.
• Characterization of N-terminal arm interactions using structural analysis techniques.

Main Results:

• Each TBSV subunit comprises two domains linked by a hinge and a flexible N-terminal arm.
• An unexpected mode of protein association was observed, with 60 N-terminal arms interdigitating in groups of three.
• The remaining 120 N-terminal arms exhibit non-unique positioning, and RNA binding sites are not fixed to major domains.

Conclusions:

• The interdigitation of N-terminal arms represents a novel mechanism for protein association in TBSV.
• The flexible and non-unique positioning of arms and RNA suggests dynamic structural properties of the viral capsid.