title: Solution structure of the helicase-interaction domain of the primase DnaG: a model for helicase activation.
abstract: The helicase-primase interaction is a critical event in DNA replication and is mediated by a putative helicase-interaction domain within the primase. The solution structure of the helicase-interaction domain of DnaG reveals that it is made up of two independent subdomains: an N-terminal six-helix module and a C-terminal two-helix module that contains the residues of the primase previously identified as important in the interaction with the helicase. We show that the two-helix module alone is sufficient for strong binding between the primase and the helicase but fails to activate the helicase; both subdomains are required for helicase activation. The six-helix module of the primase has only one close structural homolog, the N-terminal domain of the corresponding helicase. This surprising structural relationship, coupled with the differences in surface properties of the two molecules, suggests how the helicase-interaction domain may perturb the structure of the helicase and lead to activation.
authors.affiliation: Department of Molecular Biology and Biotechnology, Krebs Institute, Western Bank, University of Sheffield, Sheffield S10 2TN, United Kingdom.
authors.forename: Karl
authors.initials: K
authors.lastname: Syson
authors.forename: Jenny
authors.initials: J
authors.lastname: Thirlway
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Hounslow
authors.forename: Panos
authors.initials: P
authors.lastname: Soultanas
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Waltho
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004265:DNA Helicases / Q000378:metabolism*; D019915:DNA Primase / Q000737:chemistry / Q000378:metabolism*; D017931:DNA Primers; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D012996:Solutions
chemical_list: D017931:DNA Primers; D012996:Solutions; D019915:DNA Primase; D004265:DNA Helicases