title: Expression, purification and crystallization of the Cmi immunity protein from Escherichia coli.
abstract: Many bacteria kill related bacteria by secretion of bacteriocins. In Escherichia coli, the colicin M protein kills E. coli after uptake into the periplasm. Self-protection from destruction is provided by the co-expressed immunity protein. The colicin M immunity protein (Cmi) was cloned, overexpressed and purified to homogeneity. The correct fold of purified Cmi was analyzed by activity tests and circular-dichroism spectroscopy. Crystallization trials yielded crystals, one of which diffracted to a resolution of 1.9 Å in the orthorhombic space group C222(1). The crystal packing, with unit-cell parameters a = 66.02, b = 83.47, c = 38.30 Å, indicated the presence of one monomer in the asymmetric unit with a solvent content of 53%.
authors.affiliation: Department for Protein Evolution, Max Planck Institute for Developmental Biology, Spemannstrasse 35, D-72076 Tübingen, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Römer
authors.forename: Silke I
authors.initials: SI
authors.lastname: Patzer
authors.forename: Reinhard
authors.initials: R
authors.lastname: Albrecht
authors.forename: Kornelius
authors.initials: K
authors.lastname: Zeth
authors.forename: Volkmar
authors.initials: V
authors.lastname: Braun
mesh_terms: D003087:Colicins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry*; D015870:Gene Expression
chemical_list: D003087:Colicins