title: Crystal structure of colicin E3: implications for cell entry and ribosome inactivation.
abstract: Colicins kill E. coli by a process that involves binding to a surface receptor, entering the cell, and, finally, intoxicating it. The lethal action of colicin E3 is a specific cleavage in the ribosomal decoding A site. The crystal structure of colicin E3, reported here in a binary complex with its immunity protein (IP), reveals a Y-shaped molecule with the receptor binding domain forming a 100 A long stalk and the two globular heads of the translocation domain (T) and the catalytic domain (C) comprising the two arms. Active site residues are D510, H513, E517, and R545. IP is buried between T and C. Rather than blocking the active site, IP prevents access of the active site to the ribosome.
authors.affiliation: Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: S
authors.initials: S
authors.lastname: Soelaiman
authors.forename: K
authors.initials: K
authors.lastname: Jakes
authors.forename: N
authors.initials: N
authors.lastname: Wu
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: M
authors.initials: M
authors.lastname: Shoham
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D020134:Catalytic Domain; D003087:Colicins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012270:Ribosomes / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D003087:Colicins; D029968:Escherichia coli Proteins; C488855:ceiC protein, E coli; C007104:colicin immunity proteins