Structural studies on chimeric Sesbania mosaic virus coat protein: Revisiting SeMV assembly.
Gulati, A., Murthy, A., Abraham, A., Mohan, K., Natraj, U., Savithri, H.S., Murthy, M.R.(2015) Virology 489: 34-43
- PubMed: 26704627 
- DOI: https://doi.org/10.1016/j.virol.2015.11.029
- Primary Citation of Related Structures:  
4Y4Y, 4Y5Z - PubMed Abstract: 
The capsid protein (CP) of Sesbania mosaic virus (SeMV, a T=3 plant virus) consists of a disordered N-terminal R-domain and an ordered S-domain. Removal of the R-domain results in the formation of T=1 particles. In the current study, the R-domain was replaced with unrelated polypeptides of similar lengths: the B-domain of Staphylococcus aureus SpA, and SeMV encoded polypeptides P8 and P10. The chimeric proteins contained T=3 or larger virus-like particles (VLPs) and could not be crystallized. The presence of metal ions during purification resulted in a large number of heterogeneous nucleoprotein complexes. N∆65-B (R domain replaced with B domain) could also be purified in a dimeric form. Its crystal structure revealed T=1 particles devoid of metal ions and the B-domain was disordered. However, the B-domain was functional in N∆65-B VLPs, suggesting possible biotechnological applications. These studies illustrate the importance of N-terminal residues, metal ions and robustness of the assembly process.
Organizational Affiliation: 
Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.