title: Bacteriophage T4 gene 21 encodes two proteins essential for phage maturation.
abstract: The T4 prohead protease (T4 PPase) is the key enzyme in the morphopoietic pathway of the T4 phage head. It is responsible for the proteolytic processing of all head proteins allowing protein rearrangement and head expansion. To study its biochemistry and gene regulation, T4 gene 21 was cloned into an expression vector under the control of the inducible tac promoter. Two proteins of apparent molecular weights of 21.5 and 27.5 kDa were detected after induction. These proteins are synthesized using two different start codons in the same reading frame. Destruction of either start codon resulted in the loss of the respective protein. Complementation experiments with bacteriophage T4 21(-)-infected cells showed that both proteins are functional in vivo and essential for T4 phage assembly.
authors.affiliation: Department of Microbiology, Biozentrum, University of Basal, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Hintermann
authors.forename: A
authors.initials: A
authors.lastname: Kuhn
mesh_terms: D001483:Base Sequence; D010450:Endopeptidases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D005814:Genes, Viral; D005816:Genetic Complementation Test; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D009024:Morphogenesis; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000648:ultrastructure; D011993:Recombinant Fusion Proteins / Q000235:genetics; D013604:T-Phages / Q000235:genetics*; D014758:Viral Core Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015678:Viral Structural Proteins / Q000235:genetics*; D014779:Virus Replication
chemical_list: D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014758:Viral Core Proteins; D015678:Viral Structural Proteins; D010450:Endopeptidases; C075881:prohead protease, bacteriophage T4