title: The extreme C terminus of primase is required for interaction with DnaB at the replication fork.
abstract: We have shown previously that a protein-protein interaction between DnaG and DnaB is required to attract the primase to the replication fork. This interaction was mediated by the C-terminal 16-kDa domain (p16) of the primase. A screen was developed that allowed the detection of mutant p16 proteins that did not interact with DnaB. Various mutagenesis protocols were used to localize this interaction domain to the extreme C terminus of the primase. A mutant primase missing only the C-terminal 16 amino acids was isolated and its activities examined. This mutant enzyme was fully active as a primase, but was incapable of interacting with DnaB. Thus, the mutant primase could not support DNA synthesis in either the general priming reaction or during phiX174 complementary strand DNA replication. Alanine cluster mutagenesis and deletion analysis in p16 allowed the further localization of the interaction domain to the extreme C-terminal 8 amino acids in primase.
authors.affiliation: Graduate Program in Molecular Biology, Cornell University Graduate School of Medical Sciences, New York, New York 10021, USA.
authors.forename: K
authors.initials: K
authors.lastname: Tougu
authors.forename: K J
authors.initials: KJ
authors.lastname: Marians
mesh_terms: D000409:Alanine / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D004265:DNA Helicases; D019915:DNA Primase; D017931:DNA Primers; D004261:DNA Replication; D053488:DnaB Helicases; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D012316:RNA Nucleotidyltransferases / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004265:DNA Helicases; D053488:DnaB Helicases; D000409:Alanine