6bbm

Mechanisms of Opening and Closing of the Bacterial Replicative Helicase: The DnaB Helicase and Lambda P Helicase Loader ComplexMechanisms of Opening and Closing of the Bacterial Replicative Helicase: The DnaB Helicase and Lambda P Helicase Loader Complex

6bbm, resolution 4.10Å Show:Asymmetric Unit Biological Assembly Structural highlights 6bbm is a 11 chain structure with sequence from Bacteriophage lambda and Escherichia coli o111:nm. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: Gene: DQW49_15020 (Escherichia coli O111:NM) Activity: DNA helicase, with EC number 3.6.4.12 Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [A0A365Q7M1_ECOLX] Participates in initiation and elongation during chromosome replication; it exhibits DNA-dependent ATPase activity and contains distinct active sites for ATP binding, DNA binding, and interaction with DnaC protein, primase, and other prepriming proteins.[RuleBase:RU362085] [VRPP_LAMBD] Replication protein P is necessary for the bidirectional replication of lambda DNA. It interacts with the ori (origin of replication) region of the genome during the initiation of replication. Publication Abstract from PubMed Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and closing of the helicase, which enable and restrict access to an internal chamber, are not known. Here, we investigate these mechanisms in the Escherichia coli DnaB helicase*bacteriophage lambda helicase loader (lambdaP) complex. We show that five copies of lambdaP bind at DnaB subunit interfaces and reconfigure the helicase into an open spiral conformation that is intermediate to previously observed closed ring and closed spiral forms; reconfiguration also produces openings large enough to admit ssDNA into the inner chamber. The helicase is also observed in a restrained inactive configuration that poises it to close on activating signal, and transition to the translocation state. Our findings provide insights into helicase opening, delivery to the origin and ssDNA entry, and closing in preparation for translocation. Mechanisms of opening and closing of the bacterial replicative helicase.,Chase J, Catalano A, Noble AJ, Eng ET, Olinares PD, Molloy K, Pakotiprapha D, Samuels M, Chait B, des Georges A, Jeruzalmi D Elife. 2018 Dec 24;7. pii: 41140. doi: 10.7554/eLife.41140. PMID:30582519 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Helicase 3D structures