title: Change of a catalytic reaction carried out by a DNA replication protein.
abstract: The RepA protein of plasmid pC194 initiates and terminates rolling circle replication. At initiation, it forms a 5'-phosphotyrosyl DNA link, whereas at termination, a glutamate residue directs hydrolytic cleavage of the newly synthesized origin, and the resulting 3'-hydroxyl group undergoes transesterification with the phosphotyrosine link. The protein is thus released from DNA, and the termination is uncoupled from reinitiation of replication. Replacement of the glutamate with tyrosine in RepA altered this mechanism, so that termination occurred by two successive transesterifications and became coupled to reinitiation. This result suggests that various enzymes involved in DNA cleavage and rejoining may have similar mechanistic and evolutionary roots.
authors.affiliation: Génétique Microbienne, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy en Josas Cedex, France.
authors.forename: M F
authors.initials: MF
authors.lastname: Noirot-Gros
authors.forename: S D
authors.initials: SD
authors.lastname: Ehrlich
mesh_terms: D010584:Bacteriophage phi X 174; D001665:Binding Sites; D004265:DNA Helicases; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins; D004951:Esterification; D019143:Evolution, Molecular; D018698:Glutamic Acid / Q000378:metabolism; D006868:Hydrolysis; D009154:Mutation; D010957:Plasmids; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators; D014443:Tyrosine / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D011506:Proteins; D015534:Trans-Activators; D014764:Viral Proteins; C045264:replication initiator protein; D018698:Glutamic Acid; D014443:Tyrosine; D004265:DNA Helicases