title: The crystal structure of bacteriophage GA and a comparison of bacteriophages belonging to the major groups of Escherichia coli leviviruses.
abstract: The three-dimensional structure of the small T=3 RNA bacteriophage GA has been determined at 3.4 A resolution. The structure was solved by molecular replacement, using the phage MS2 as an initial model. A comparison of the protein shells of the four related phages GA, MS2, fr and Qbeta was carried out in order to define structural features of particular importance for their assembly and specific RNA interaction. A high degree of similarity was found in the RNA binding sites, whereas larger structural differences are located in the loop regions of the coat proteins, especially in the FG loops forming 5-fold and quasi-6-fold contacts. The overall arrangement of the protein subunits in the shells of these phages is very similar, although the details of the interactions differ. The few conserved interactions are suggested to govern the subunit packing during assembly.
authors.affiliation: Biomedical Research and Study Centre, Latvian University, Ratsupites 1, Riga, Latvia.
authors.forename: K
authors.initials: K
authors.lastname: Tars
authors.forename: M
authors.initials: M
authors.lastname: Bundule
authors.forename: K
authors.initials: K
authors.lastname: Fridborg
authors.forename: L
authors.initials: L
authors.lastname: Liljas
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002213:Capsid / Q000737:chemistry*; D003090:Coliphages / Q000737:chemistry*; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D019281:Dimerization; D017909:Levivirus / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012317:RNA Phages / Q000737:chemistry*; D012367:RNA, Viral / Q000737:chemistry; D019065:Virus Assembly
chemical_list: D012367:RNA, Viral