title: The solution structures of two prophage homologues of the bacteriophage λ Ea8.5 protein reveal a newly discovered hybrid homeodomain/zinc-finger fold.
abstract: A cluster of genes in the exoxis region of bacteriophage λ are capable of inhibiting the initiation of DNA synthesis in Escherichia coli. The most indispensible gene in this region is ea8.5. Here, we report the nuclear magnetic resonance structures of two ea8.5 orthologs from enteropathogenic E. coli and Pseudomonas putida prophages. Both proteins are characterized by a fused homeodomain/zinc-finger fold that escaped detection by primary sequence search methods. While these folds are both associated with a nucleic acid binding function, the amino acid composition suggests otherwise, leading to the possibility that Ea8.5 associates with other viral and host proteins.
authors.affiliation: Department of Biology, York University , 4700 Keele Street, Toronto, ON M3J1P3, Canada.
authors.forename: Jamie J
authors.initials: JJ
authors.lastname: Kwan
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Smirnova
authors.forename: Shahin
authors.initials: S
authors.lastname: Khazai
authors.forename: Ferenc
authors.initials: F
authors.lastname: Evanics
authors.forename: Karen L
authors.initials: KL
authors.lastname: Maxwell
authors.forename: Logan W
authors.initials: LW
authors.lastname: Donaldson
mesh_terms: D000595:Amino Acid Sequence; D010582:Bacteriophage lambda / Q000737:chemistry*; D003090:Coliphages / Q000737:chemistry; D018398:Homeodomain Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D039002:Prophages / Q000737:chemistry*; D011487:Protein Conformation; D017105:Pseudomonas Phages / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry*; D016335:Zinc Fingers
chemical_list: D018398:Homeodomain Proteins; D014764:Viral Proteins