title: Structural studies on chimeric Sesbania mosaic virus coat protein: Revisiting SeMV assembly.
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.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Gulati
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Abhinandan
authors.initials: A
authors.lastname: Murthy
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Ambily
authors.initials: A
authors.lastname: Abraham
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Kalyani
authors.initials: K
authors.lastname: Mohan
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Usha
authors.initials: U
authors.lastname: Natraj
authors.affiliation: Department of Biochemistry, Indian Institute of Science, Bangalore 560012, India.
authors.forename: H S
authors.initials: HS
authors.lastname: Savithri
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India. Electronic address: mrn@mbu.iisc.ernet.in.
authors.forename: M R N
authors.initials: MR
authors.lastname: Murthy
mesh_terms: D036022:Capsid Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008670:Metals / Q000378:metabolism; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D012328:RNA Viruses / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D036022:Capsid Proteins; D008670:Metals
keywords: Chimeric VLPs; Coat protein; R-domain; S. aureus B-domain; SeMV; SeMV assembly; SeMV polypeptides P10 and P8; Virus nano-particles