title: Purification and crystallization of CII: an unstable transcription activator from phage lambda.
abstract: The CII protein of the temperate bacteriophage lambda is a transcriptional activator involved in the lysis-lysogeny switch of the phage. It is an unstable protein of 97 amino acids and is known to exist as a tetramer in the native state. The cII gene has been cloned and expressed in Escherichia coli using a T7 promoter based over-expression system. The recombinant CII protein has been purified to homogeneity by ammonium sulfate fractionation followed by two steps of ion-exchange chromatography. The purified protein crystallized at pH 8.2 in hanging-drop vapor diffusion method at 293 K. The crystals diffract to a resolution of 2.8 A and belong to the space group C222 with unit-cell parameters a = 64.10, b = 106.95 and c = 120.16 A.
authors.affiliation: Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Kolkata, 700054, India.
authors.forename: A B
authors.initials: AB
authors.lastname: Datta
authors.forename: P
authors.initials: P
authors.lastname: Chakrabarti
authors.forename: H S
authors.initials: HS
authors.lastname: Subramanya
authors.forename: P
authors.initials: P
authors.lastname: Parrack
mesh_terms: D010582:Bacteriophage lambda / Q000737:chemistry* / Q000235:genetics; D003460:Crystallization; D004591:Electrophoresis, Polyacrylamide Gel; D013816:Thermodynamics; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification*; D014764:Viral Proteins; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D014157:Transcription Factors; D014764:Viral Proteins; C039000:cII protein, bacteriophage lambda