Characterization of polymorphism displayed by the coat protein mutants of tomato bushy stunt virus.
Expression of full-length and N-terminal deletion mutants of the coat protein (CP) of tomato bushy stunt virus (TBSV) using the recombinant baculovirus system resulted in spontaneously assembled virus-like particles (VLPs). Deletion of the majority of the R-domain sequence of the CP, residues 1-52 (CP-NDelta52) and 1-62 (CP-NDelta62), produced capsids similar to wild-type VLPs. Interestingly, the CP-NDelta62 mutant that retains the last 3 residues of R-domain is capable of forming both the T = 1 and T = 3 particles. However, between the two types of VLPs, formation of the T = 1 capsids appears to be preferred. Another mutant, CP-NDelta72, in which R-domain (residues 1-65) was completely removed but contains most of the beta-annulus and extended arm (betaA) regions exclusively formed T = 1 particles. These results suggest that as few as 3 residues (63-65) of the R-domain, which includes 2 basic amino acids together with the arm (betaA) and beta-annulus regions, may be sufficient for the formation of T = 3 particles. However, anywhere between 4 to 13 residues of the R-domain may be required for proper positioning of betaA and beta-annulus structural elements of the C-type subunits to facilitate an error free assembly of T = 3 capsids.
Hsu
Catherine
C
Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Singh
Pratik
P
Ochoa
Wendy
W
Manayani
Darly J
DJ
Manchester
Marianne
M
Schneemann
Anette
A
Reddy
Vijay S
VS
D000595:Amino Acid Sequence; D000818:Animals; D002213:Capsid / Q000378:metabolism / Q000648:ultrastructure; D036022:Capsid Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002460:Cell Line; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D017434:Protein Structure, Tertiary / Q000235:genetics / Q000502:physiology; D012367:RNA, Viral / Q000032:analysis; D016415:Sequence Alignment; D017384:Sequence Deletion; D018411:Spodoptera; D017864:Tombusvirus / Q000235:genetics* / Q000648:ultrastructure; D022701:Virosomes / Q000378:metabolism* / Q000648:ultrastructure*
D036022:Capsid Proteins; D012367:RNA, Viral; D022701:Virosomes