title: Structure determination of the bacteriophage MS2.
abstract: The structure of the bacterial virus MS2 has been solved at 3.3 A resolution. Initial phases to 13 A resolution were obtained from a model based on the known coordinates of the plant virus southern bean mosaic virus. These phases were extended in small steps to a resolution of 3.4 A. The phases obtained represented essentially the Babinet opposite of the true structure and were not of a sufficiently good quality to allow an interpretation of the electron density contoured at negative levels. Difference Fourier maps of two heavy-atom derivatives based on these phases were interpretable, and these derivatives were used to calculate isomorphous replacement phases at 8.8 A resolution. Phase extension to 3.3 A resolution led to maps which could be easily interpreted.
authors.affiliation: Department of Molecular Biology, Uppsala University, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Valegård
authors.forename: L
authors.initials: L
authors.lastname: Liljas
authors.forename: K
authors.initials: K
authors.lastname: Fridborg
authors.forename: T
authors.initials: T
authors.lastname: Unge
mesh_terms: D001435:Bacteriophages / Q000737:chemistry*; D003460:Crystallization; D004583:Electrons; D005583:Fourier Analysis; D015394:Molecular Structure; D014771:Virion / Q000737:chemistry; D014961:X-Ray Diffraction