title: Ribonucleoprotein complexes of R17 coat protein and a translational operator analog.
abstract: The coat protein of the simple spherical (triangulation no. T = 3) RNA coliphage R17 protects the genomic RNA in the virus particle and acts as a translational repressor of the phage-encoded replicase gene. It has been suggested that these two functions are related and that the translational repression complex serves as a nucleation complex for subsequent assembly of the bacteriophage. We have used a translational operation fragment to examine the relationship between formation of the translational repression complex and the assembly of the protein into T = 3 capsids. In vitro analysis of the aggregation properties of R17 coat protein reveals that binding of the translational operator fragment to the protein dimer triggers polymerization of the protein into T = 3 capsids of well-defined composition. The data further implicate the translational operator in nucleation of assembly and suggest a possible physical-chemical basis of the nucleation step.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder 80309-0215.
authors.forename: D
authors.initials: D
authors.lastname: Beckett
authors.forename: O C
authors.initials: OC
authors.lastname: Uhlenbeck
mesh_terms: D001483:Base Sequence; D002213:Capsid / Q000235:genetics* / Q000378:metabolism; D036022:Capsid Proteins; D003090:Coliphages / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D009875:Operator Regions, Genetic; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins / Q000235:genetics* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D036022:Capsid Proteins; D046911:Macromolecular Substances; D012367:RNA, Viral; D016601:RNA-Binding Proteins; D012261:Ribonucleoproteins